ANDROLOGIA

ACCEPTED: MARCH6, 1992

24, 183-196 (1992)

Review

Morphology and functions of the human seminal vesicle G. Aumiiller' and A. Riva' Key words. Human seminal vesicle - development - malformations - secretion - resorption - spermatophagy - semen analysis.

Summary. The seminal vesicles originate in embryos of about 58 mm crown-rump-length from the Wolffian duct under the influence of testosterone. Along with the ampulla of the vas deferens and the ejaculatory duct, they form a functional unit that develops slowly until the onset of puberty. Developmental malformations occur as uni- or bilateral agenesis, aplasia, cysts, or ureterovesicular fistules. After puberty, the glands form sac-like structures which have a capacity of about 3.4-4.5 ccm and contribute about 70% of the seminal fluid. I n addition to secretion, they are capable of reabsorption of fluids or dissolved substances, and of spermatophagy (ingestion and degradation of damaged spermatozoa by epithelial cells). Secretory activity of the glands is a measure of testosterone supplementation to the epithelium. Nervous regulation of secretion is realized by cholinergic post-ganglionic, sympathetic (and perhaps parasympathetic) fibres, derived from pelvic plexus. Contraction of the muscular wall occurs under the influence of excitatory adrenergic and modulatory NPY-encephalin-peptidergic nerve fibres. The secretory products of the seminal vesicles encompass ( 1 ) ions ( K f : 1.1 mM ml-') (2) low molecular weight substances (fructose: above 1.2 mg ml- I ; prostaglandins above 250 p1 ml- I , (3) peptides (endorphin: 330 pg ml-'), and (4) proteins. I n addition to plasma protein related forms such as transferrin, lactoferrin, and fibronectin, specific proteins such as semenogelin (52 kDa) are synthesized, the scaffold protein of semen coagulate forming the substrate for PSA 'Department of Anatomy and Cell Biology, Philipps University D-3550 Marburg, Germany and 'Department of Cytomorphology, University of Cagliari, 1-09124 Cagliari, Italy. Correspondence: G. Aumiiller, Department of Anatomy and Cell Biology, Philipps University D-3550 Marburg, Germany.

(prostate specific antigen), sperm motility inhibitor (ca. 18 kDa), and others (placental protein 5, protein kinase inhibitor, carboanhydrase, 5'nucleotidase) , some of which are immunosuppressive. Therefore, functions of the seminal vesicles concern (a) formation of seminal coagulum, (b) modification of sperm functions (motility, capacitation) , and (c) immunosuppression. Additional functions within the female genital system, perhaps during pre-implantation period, are likely, but remain to be proven experimentally. Introduction

T h e seminal vesicles were described for the first time in 1521 by the Italian anatomist Berengario a Carpi. They were regarded as mere storage organs for semen, hence the designation seminal vesicles (for summary of morphology see: Aumuller, 1979). Recent morphological studies (see: Riva et al., 1989) have shown that the seminal vesicles along with the ampulla of the deferent ducts and the ejaculatory duct can be regarded as a functional unit (ampullo-vesiculoductal complex). Its functions consist in: resorption, spermatophagy, and secretion. I n some species the seminal vesicles are lacking (e.g. dog) or the ampulla is absent (Shalev et al., 1983), while in others they are fairly large (guinea pig). There are two basic forms ( 1 ) the saccular type (rat, horse, human), and (2) the tubuloglandular type (pig, bull). Development, developmental alterations, maturation, and involution

Development T h e anlage of the organ develops in embryos of 50-65 mm in length (12th week of pregnancy)

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as a spindle-like dilation forming in the distal Wolffian duct (Brewster, 1985). I n embryos of 80 mm in length (week 14) the separation into ampulla and lateral diverticulum of seminal vesicle develops. T h e seminal vesicle transforms into a hook-like duct, in which most of the side ducts form during month 4-5 of pregnancy. Until birth, the growth of the seminal vesicle continues and the interior of the gland differentiates by the formation of connective tissue strands and ridges, as well as the differentiation of the smooth muscle cells within the seminal vesicle wall. During this time the gland consists of a main duct with 9-12 diverticula. Simultaneously, the distal end of the vas deferens has developed into the ampulla (Fig. 1). T h e terminal portion of the Wolffian duct is surrounded by the prostatic tissue and has retained its narrow lumen. I n place of smooth muscle cells this portion is surrounded by a venous plexus and forms the ejaculatory duct. Malformations

Loss of separation of the secondary ureter from the Wolffian duct close to its ending in the urogenital sinus results in a ureterovesicular fistula (ectopic termination of the ipsilateral ureter in the seminal vesicle). Characteristic symptoms are recurrent inflammations, and typical radiological findings, and additional forms are uni- or bilateral agenesis or aplasia of the seminal vesicles (Colpi et al., 1990, Weidner, 1991), formation of cysts and occlusion of the ejaculatory ducts.

Figure 1. Seminal vesicle of a neonatal boy. Immunohistochemical demonstration of smooth muscle cells using an antibody against actin. ‘the epithelium covers a thick, poorly differentiated layer of connective tissue. x 300 Figure 2. Seminal vesicle of a 5 year old boy. Clumsy folds of connective tissue are covered by a high epithelium. The basal cells of the epithelium are stained using a cytoceratin antibody. x 300

Characteristic changes in the ejaculate in cases of bilateral occlusion are azoospermia, low levels or lacking seminal fructose, high levels of acid phosphatase and acidic p H value. Pubertal maturation Until puberty development proceeds slowly (Table 1 ) . I n the child, the epithelium of the seminal vesicles consists of basal and mucus-producing glandular cells (Fig. 2). During puberty the glandular weight increases by a factor of 10. Connective tissue and smooth muscle cells increase in amount and the gland develops the typical septation of the interior. T h e epithelium decreases in height and gains in width and starts to secrete. Simultaneously, lipofuscin granules are seen within the epithelial cells (indicating spermatophagy, see Fig. 3 ) . In uo lu tion After 45 years of life the muscular system of the Table 1. T h e progress of puberty

Neonatal 1 Year 1-5 Years 8- 10 Years 12 Years 14 Years 15 Years

0.05 0.08 0.09 0.1 0.12 0.15 1.5

10 15 17 20 25 22 61

3.3 4.0 4.0 4.2 4.0 4.0 6.6

Figure 3. Seminal vesicle of a 22 year old man (gallocyanin stain). The large nuclei of the epithelium are rich in chromatin. Notice the large amount of spermatozoa present in the lumen. x 650 Figure 4. Immunohistochemical demonstration of semenogelin in seminal vesicle epithelium of a normal adult (The antibody against semenogelin is a courtesy of Professor H . Lilja, Malmo, Sweden). The epithelium stains irregularly hut relatively strongly. x 500

ANDROLOGIA 24, 183-196 (1992)

HUMAN SEMINAL VESICLE: MORPHOLOGY

organ is reduced and regressive changes occur. These include a decrease in secretion content of the glandular cells, development of polyploid or giant nuclei, atrophy of musculature, hyalinization of the basal membranes, sclerosis of connective tissue and a reduction of organ volume.

Topographic situation and gross anatomy Situation The seminal vesicals rest in the connective tissue lodge interspersed between the urinary bladder and the rectum lateral to the ampulla of the ducts deferens. Apically they are in contact with the ureter and the adjacent bundle of nerves and blood vessles as well as with the peritoneum. T h e so-called Denonvilliers fascia forms the dorsal boundary with the rectum.

Form The connection between ampulla, seminal vesicle, and ejacutory ducts is rather variable. I n 75% of all cases direct continuation of the main duct of the seminal vesicles into the ejaculatory duct into which the ampulla of the vas deferens merges medially. An equal angular fusion of the main duct and the ampulla into the ejaculatory duct is found in less than 25% of all cases and in 10% a direct continuation of the ampulla into the ejaculatory duct and lateral fusion of the main duct of the seminal vesicle exists. Three main forms of the organ are described (Aboul-Azm, 1979): a channel with several coils and lacking buds, a channel with the few coils, few side buds and diverticula, and an ascending main duct with hook like descending end and several diverticula on the base.

The ejaculatory ducts or thejnal portion of the system They pass through the prostate in a ventrally concave crescent, and reach the lateral urethal surface of the verum montanum a t an angle of 35-40', where they sharply curve caudally. Their length amounts to about 2.2-2.6 cm. Measures (from Aboul-Azm, 1979; Aumuller, 1979); length: 40-50 mm (average 47); thickness: 12- 17 mm (average 17); volume/capacity: 2.5-4.5 cm (average 4); weight: 5.8-8.8 g (average 7.5); Type of Form: ( 1 ) :31y0, (2) 40%, (3) 29% ANDROLOGIA 24, 183-196 (1992)

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Vascular suppb Vessels are derived from the superior and medial rectal artery, the artery of the vas deferens and the inferior vesical artery which form three bundles of vessels (dorsal superior, dorsal inferior, and anterior bundle), form extended anastomoses. T h e veins are arranged in a dense organ plexus merging into few candal thicker veins which drain into the prostatic deferential venous plexus. The lymph vessels are connected with the urether and the hypogastric lymph nodes. Into the latter the very rare seminal vesicle carcinomas metastasize (Tanaka et al., 1987).

Innervation Nerve fibres reaching the ventral-medial aspect of the glands, containing intramural ganglia are derived from the pelvic plexus, which is formed from lumbal sympathetic and sacral parasympathetic portions, as well as fibres from the inferior hypogastric and rectovesical plexus. They contain adrenergic, cholinergic, and (age-dependent), proenkephalin-opioidergic neurons (Aumuller et al., 1989). These supply the musculature of the seminal vesicles and the ampulla of the vas deferens.

Histology Connective tissue The interior surface of the gland is separated by a dense system of connective tissue meshwork that shows a different arrangement in the various portions in the gland. The strands of connective tissue close to the central lumen of the gland are often very broad and bandlike. The epithelium covering these strands of connective tissue is mostly slightly less high than that found in the deeper portions piercing into the smooth muscular wall. Close to the main duct of the gland the amount of elastic connective tissue fibres increases.

Musculature of the seminal vesicles This forms an interlacing system of broad strands of smooth muscle cells with different orientation, forming 2-3 or sometimes up to 5 layers, and surround in a hose-like manner the main duct and the diverticula of the gland. Blood vessels pierce through the muscle layer and form a dense capillary network within the sub-epithelial tissue. Closely adjacent, a network of adrenergic nerves is found. I n the subepithelial portion, the nerves are preferentially cholinergic.

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Epithelium The epithelium consists of basal and glandular cells and rests on a basement membrane containing numerous elastic and agyrophil fibres. The secretory cells of the seminal vesicle epithelium measure about 15-24 pm (Fig. 4). They rest on the layer of flat basal cells (5-9 pm) which sometimes appear rounded, but never reach the lumen. The nuclei of the glandular cells reside in the basal third of the cells and contain a rich amount of chromatin. They are surrounded by a loosely arranged cytoplasm with several lipofuscin granules. Apically, numerous eosinophilic secretory granules are detected that form a homogeneous compound outside the cells giving a strong PAS reaction. I n addition to that, acidic mucopolysaccharides are seen forming a loose precipitate within the lumen. Enzyme histochemistry

Figure 5. Survey electron micrograph of seminal vesicle epithelium of a 52 year old man. The glandular cells contain large lipofuscin inclusions and electron dense secretion granules. x 4000 Figure 6. Epithelial cell of the duct type (non-secretory)-cellfrom the proximal portion of the seminal vesicle. X 3500

Cossu and co-workers (1978) have detected a strong activity of glucose-6-phosphatedehydrogenase and the D-sorbitol-dehydrogenase in the epithelium of the seminal vesicles and the ampulla of the vas deferens which are in favour of the production of fructose by an oxidative metabolic pathway. I n addition, the epithelium contains 17p-, 3p-, and 3a-steroid-dehydrogenase activity. This seems to indicate the presence of 5a-dihydrotestosterone in seminal vesicle epithelium (Sirigu et al., 1981).

Ultrastructure Epithelia of the seminal vesicle, the ampulla of the vas deferens and ejaculatory duct share a common ultrastructure i.e. a common cell type (Fig. 5). Therefore the organs can be put together as an ampullo-vesiculo-ductal complex. A detailed description of ultrastructure is not necessary (for review see: Aumuller et al., 1979; Riva et al. 1982; Cossu et al., 1983; Riva et al., 1989). The formerly described so-called duct cells containing short stubby microvilli, numerous micropinocytosis vesicles, and relatively sparse secretion granules have been identified as resting cells from the secretion cycle, since transition forms are observed between highly active and inactive cell types (Fig. 6). According to Riva et al. (1989), about 50% of all glandular cells in men aged 40-50 years are of that type, while in 71-80 year old men up to 98% of the epithelium is formed of cuboid cells, while only 2% form large glandular cells (Figs. 7 and 8). Subsequent to antiandrogen treatment cuboidal cells appear most prominent (Figs. 9 and 10). Whether or not their

Figure 7. High magnification of the epical portion of a secretory cell showing endoplasmic reticulum, mitochondria, and secretory granules surrounded by a halo. x 12000 Figure 8. I n addition to intracellular and extruded secretion granules (s) also micropinocytosis vesicles (v) and so-called coated vesicles (cv) occur in the apical portion of the cell. x 17500

content in apically located micropinocytosis vesicles are in favour of a n increased resorbtive activity, is difficult to decide from the ultrastructural finding, but it seems likely.

Histophysiology T h e essential functions of the ampullo-vesicularductal complex are: ( 1 ) secretion, (2) resorption, and (3) spermatophagy. These functions occur at different intensities in various portions of the organ. Taking ultrastructural (secretion granules, pinocytosis vesicles, lipofuscin, dense bodies), and comparative anatomical data as indicators for the different funcANDROLOGIA 24, 183-196 (1992)

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Figure 9. Survey electron micrograph of seminal vesicle epithelium after long term androgen deprivation. The epithelium ( e ) is largely atrophic, while muscle cells appear nearly intact. x 8400 Figure 10. High magnification of epithelium after androgen deprivation. The cells are poor in cytoplasmic organelles but contain several vesicles and some ischaemia-damaged mitochondria. x 15000

tions, the following specialization of the different portions of the complex is likely: Secretion Spermatophagy Ampulla Seminal vesicles Ejaculatory duct

++ +++ +

++

+ +++

Resorption

+++ ++ +++

Nervous and hormonal regulation of seminal vesical function Innervation Centres of innervation: sympathetic innervation of the seminal vesicles originates in lumbar segments ( L,-L4), the superior hypogastric plexus and the parasympathetic Nn. erigentes (S,-S,) which form the pelvic plexus. This also receives direct fibres from the sacral sympathetic trunk and which may be divided into posterior rectal, superior uretero-vesicle, and inferior vesiculo-urethroprostatic portion. Structure of the vesiculo-prostaticodeferential plexus (plexus pelvicus) : typical of this plexus, are post-ganglionic sympathetic pre- and post-ganglionic parasympathetic neurons containing small catecholamin-containing, and large acetylcholinesterase-containing perikarya and fibres, as well as numerous SIF-cells. I n younger individuals numerous proenkephalin-octapeptide and large leu-enkephalinANDROLOGIA 24, 183-196 (1992)

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containing ganglionic cells occur (Aumuller et al., 1989). (3) Organ plexus: the wall contains a dense system of cholinergic and adrenergic nerve fibres which may be subdivided as muscular, perivascular and subepithelial plexus (El Badawi & Goodman, 1980). Single NPY, -VIP and leu-enkephalin-immunoreactive fibres have been described. The presence of substance P-containing fibres is doubtful. (4)Functions: innervation of the musculature by a-adrenergic excitatory fibres has been verified. T h e contribution of j3-adrenergic inhibitory of presynaptic adrenergic inhibitory or NPY-peptigernic elements is discussed. It is not clear, whether or not the secretion is stimulated by cholinergic post-ganglionic sympathetic and auxiliary j3-adrenergic fibres, or by post-ganglionic parasympathetic neurons. I n laboratory animals, histamine receptors in seminal vesicle tissue have been found. (5) Experimental: in vitro seminal vesicle epithelium of the rat cultured in vitro requires presence of neurotransmitters (acetylcholin, adrenalin, serotonin), for the androgendependent synthesis of secretory proteins. Possibly, the phosphatidyl-inositol pathway for stimulation of secretion is used (Kinghorn et al., 1987). A very effective model for the secretion studies is found in the so-called ‘everted seminal vesicle sac’ of the guinea Pig. Hormonal regulation Androgens: the hormones essential for the function of seminal vesicles are the androgenes since after orchidectomy synthetic capacity of the organ breaks down within a few hours and involution processes start. (For a review see Aumuller & Seitz, 1990). Antiandrogen treatment in human also leads to involution of the organ. The secretory activity eg. for fructose of the seminal vesicle is used as a measure of androgen supply of the organ (Mann & Lutwak-Mann, 1981). Androgen receptor: Shan et al. (1990) have shown that in rat seminal vesicle mRNA androgen receptors are present. After castration within 24 h the amount doubly increases, and 48 h later by a factor 10. Therefore, the androgen receptor of the seminal vesicles appears to have a similar regulatory mechanism (down-regulation by the ligand dihydrotestosterone) as this is described in other androgen target organs. Oestrogens: in castrated, adrenalectomited

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animals, oestrogen treatment at a certain level results in a weight increase which however, is due, to an increase in fibromuscular stroma. The stimulatory effect of prolactin described by several authors in seminal vesicles is thought to be managed directly by prolactin receptors, as well as in an indirect manner by oestrogens.

female genital system after copulation (follicular cells, epithelium of the Fallopian tube, and uterine granulocytes).

Distribution I n a male genital system spermatophagy is observed in Sertoli cells, in rete testis, and in epididymis intensively after vasectomy (Holstein, 1978).

Resorption Distribution Immunohistochemical studies of prostate sections using antibodies against secretory prostatic proteins (acid phosphatase, prostate specific antigen, P-microseminoprotein) results in a staining of individual cells of the epithelium of the ejaculatory duct in addition to the homogeneously reacting prostatic epithelium. Since the ejaculatory duct cells simultaneously are also positive for seminal vesicle protein (semenogelin) and the immunoreaction for prostatic proteins is significantly less intense. This may be interpreted as a resorption of prostatic secretion by the epithelial cells of the ejaculatory duct which has reached the area by reflux.

Experimental Mata & Maunsbach (1982) have performed experimental studies on the resorptive activities of hamster rate seminal vesicle. '251-labelled secretion of seminal vesicle was injected into the glandular lumen and the organ was incubated in vitro for 17 and 45 min, respectively. Subsequently the tissue was processed for EM-autoradiography and evaluated quantitively. An intra- or transcellular transport was found, i.e. 45 min after labelling radioactivity was detected in subepithelial vessels. Intracellularly, the labelling was found initially in multi-vesicular bodies and subsequently in the Golgi area. As with the secretory protein of the organ, other proteins such as horseradish peroxidase is resorbed by seminal vesicle epithelium.

Ampullo-vesiculo-ductal complex I n seminal vesicles, ampulla of the vas deferens and the ejaculatory duct of different laboratory animals (Murakami & Yokoyama, 1989) and man (Riva et al., 1981), spermatophagy is performed mostly by macrophages. Preferentially, however, it is effected by adluminal epithelial cells. Using the scanning electron microscope Riva and co-workers ( 1989) regularly observed spermatozoa with the normal or shrunken heads at the inner surface of the human seminal vesicle, ampulla, and ejaculatory duct.

Process of spermatophagy The ingestion of spermatozoa by elongated, smoothly formed apices of the glandular cells which have a different length, starts at the sperm head, the posterior tail region, and preferentially in the middle piece of the tail, surrounding these structures by flattened portions of the plasma membrane of glandular cells (Figs. 11 and 12). Microvilli are mostly not directly involved in this action. Frequently, spermatozoa appear to sink longitudinally within the apical plasma membrane of the epithelial cells, or the sperm head is detached. The ingested sperm fragments coalesce with lysosomes and the forming endosomal complex is surrounded by a sheath of microfilaments and microtubules (Figs. 13 and 14). Sperm heads are rapidly degraded inside the cells. Sometimes chromatin residues, dense bodies or lipid droplets can be seen.

Lipofuscin

Spermatophagy Definition Spermatophagy is the intracellular ingestion and degradation of altered sperm or non-ejaculated spermatozoa within the male genital system by cells such as intraluminal macrophages and adluminal epithelial cells. It also occurs within the

Contrary to our previous opinion (Aumiiller, 1979), we now feel it likely that lipofuscin present in epithelium of the ampulla, seminal vesicle, and ejaculatory duct, is derived from degraded spermatozoa, perhaps also from secretory residues. I n general, spermatophagy in seminal vesicles seems to be a physiological, but not very often seen process. Dimensions and increase in number with age of lipofuscin granules and the relatively rarely ANDROLOGIA 24, 183-196 (1992)

HUMAN SEMINAL VESICLE: MORPHOLOGY

Figure 11. Survey scanning electron micrograph of the inner surface of the canine ampulla of the vas deferens. Spermatozoon is phagocytozed by the epithelium starting at the head. x 2500 Figure 12. Scanning electron micrograph of seminal vesicle epithelium (49 years old man). The head of a sperm undergoing phagocytosis protrudes from the apical portion of a principal cell. x 4200

Figure 13. Survey electron micrograph of phagocytozed spermatozoa inside the eoithelium of the canine ampulla of the vas deferens. x 3500 Figure 14. Higher magnification of the same specimen. The phagocytozed sperm head (sp) is surrounded by several microfilaments (mf) and microtubules (mt). I n the neighbourhood several Golgi vesicles and primary lysosomes (v) occur. x 14200

observed ingestion of spermatozoa by epithelium is in favour of a rapidly occuring initial ingestion during spermatophagy and a prolonged degradation phase.

Secretion

Analytical methods of the study of seminal vesicle secretion

(1) Yield: Balerna and co-workers ( 1990) have pointed to the different possibilities of yieldANDROLOGIA 24, 183-196 (1992)

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ing seminal vesicle secretion which each have advantages and disadvantages of their own. A number of biochemical processes and interactions both in vivo and in vitro may have an influence on the pattern, especially of proteins, but also of other components. The following methods are distinguished: (a) yield of ejaculate in the presence of protease inhibitors, (b) use of split ejaculate, (c) use of biopsy (aspiration) or autopsy specimens, (d) use of organ exprimate (Montagnon et al., 1990), and (e) an indirect method is the analysis of ejaculates in cases of agenesis of seminal vesicle. Study of the ejaculate: When using ejaculates, significant inter- and intraindividual differences, and a broad range of variation between values of different seminal samples are observed. Time lag between yield .and initiation of analysis is of particular significance (degradation and polymerization processes). Contrary to the aspiration-material in ejaculates, the contamination with secretion from the prostate or products from the different portions of the genital tract, usually have to be taken into account. In addition, insufficient sexual abstinence or inflammations can interfere with the protein pattern. Finally, the selection of the analytical determination system is one factor influencing the degree of precision, reproducibility, and comparability of the analytical results. Standardization: Montagnon et al. (1990) recommend the following procedure for yield of seminal plasma: after liquefaction within 30 min after yield (and at least 4 d of sexual abstinence), the samples are centrifuged at low speed (15 min at 1500 rpm) to remove spermatozoa and detritus. The supernatant is then frozen in liquid nitrogen until used. For analysis of proteins which usually occurs less frequently, the ejaculate is frozen in liquid nitrogen immediately after yield. Correlation between seminal vesicle secretion and sperm motility: Sperm motility is reduced in the third i.e. in the seminal vesicle fraction of a split ejaculate. However, the viability of the spermatozoa is better in the third rather than in the first i.e. the prostate fraction (Clavert et al., 1990). I n general, motility is better, if the fructose content of the specimen ranges between 2-6 mg ml-'. A decrease or increase of seminal vesicle secretion usually results in decreased viability of spermatozoa. Contrary to that, loss of motility during cryoconservation is more fre-

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quently observed in the third fraction rather than in the first one (Clavert et al., 1990).

Volume and characteristics The relative proportion of seminal vesicle secretion in the total volume of ejaculate ranges between 60 and 70%. Taking a volume of ejaculate in the range 1.5-6 ml, the volume of the seminal vesicle secretion accounts for 1-4.6 ml. About half of the total secretion is discharged during one ejaculation. The secretion has a slightly yellowish tint derived from the flavoproteins present, and depending on the amount of spermatozoa, it shows a different density of staining. The p H value is slightly alkaline (7.6-8.0). The consistency is initially gelatinous. Protein content amounts to about 26 mg ml-' i.e. about 50% of blood serum protein value.

Composition Survey: Seminal vesicle secretion contains: (a) ions (e.g. K + ) , (b) low molecular weight substances (e.g. fructose, phospholipids, prostaglandins), (c) peptides (e.g. glutathion, endorphin) and (d) proteins (transport proteins, structural proteins, sperm-modulating-proteins, immunosuppressive proteins, enzymes, enzyme inhibitors). A detailed analysis is given in the books of Shivaji et al. (1990) and of Mann & Lutwak-Mann (1981). When analysing the physiological effects of the seminal plasma interactions of (i) the secretion of prostate and seminal vesicle, (ii) secretions with spermatozoa, and (iii) effects on female genital system, have to be taken into account. The latter has been termed 'transsecretion', since products from one organism initiate physiological events in a different organism, e.g. uterine contractions elicited by prostaglandins or immunosuppression in the female genital system by certain seminal vesicle proteins.

Ions Content of the seminal plasma in potassium amounts 27.2f5,3 mM ( = 1,l mg ml-I); the content in sodium amounts I l S k 65 mM ( = 3,3 mg ml-I). The ratio N a + : K + should exceed 1:2.5 to secure a sufficient sperm motility (Shivaji et al. 1990). Elevated K + values have been reported to increase the electric charge of the sperm membrane ( - 16 mV), which is responsible for the increasing immobility of spermatozoa.

Low molecular substances Amino acids: after ejaculation the content in free amino acid increases considerably. This seems to be the result of proteolytical degradation of seminal vesicle secretion proteins by prostate-derived proteases. Amino acids have been regarded to function as ligands for metal ions or oxidizable substrates for the energy metabolism of spermatozoa and to contribute to the buffer capacity of seminal plasma (Shivaji et al., 1990). Prostaglandins (PG): human seminal plasma is the body fluid showing the highest content in prostaglandins. About 20 different prostaglandin derivatives have been identified in seminal plasma. The most frequently occuring forms are PGE-1 and PGE-2 and their 19-hydroxylated derivatives ( 19-OH PGE-I and 19-OH PGE-2: 267 pg ml-I). I n general, radioimmunoassays (RIA) are used a t present for prostaglandin determinations. In addition, methods of gas chromatography and HPLC have been described (Shivaji et al., 1990). The role of prostaglandins during regulation of sperm motility is controversial, as no direct correlation between the concentration of different prostaglandins and sperm motility has been found. Perhaps motility depends on an optimal concentration ratio between different prostaglandins. Fructose/Glucose: fructose was detected in 1945 by T. Mann as the essential reducing sugar in seminal plasma. I n principle, three different metabolic ways of synthesis may account for biosynthesis of fructose which originates from blood glucose (Mann & Lutwak-Mann, 1981) : (a) glycogenolysis, (b) direct phosphorylation by hexocinase and ATP forming glucose-6-phosphate, isomerization to fructose-6-phosphate and hydrolysis into free fructose, and (c) the nonphosphorylating metabolic pathway through reduction of glucose in the presence of NADPH by aldose reductase forming sorbitol and oxidation of sorbitol in the presence of NAD by sorbitol dehydrogenase resulting in free fructose. The presence of enzymehistochemically demonstrable strong sorbitol dehydrogenase activity and an NADPH-generating system in seminal vesicle epithelium are in favour of the latter pathway. Methods of determination: in addition to the old fashioned colorimetric test, commercial enzymatic kits are available based on the d-fructose dehydrogenase system. The norm value ranges between 6 and 60 p~ ml-'. ANDROLOGIA 24, 183-196 (1992)

HUMAN SEMINAL VESICLE: MORPHOLOGY

(5) Pitfalls: Balerna et al. (1990) have pointed to the correlation between liquefaction time and fructose content between 20 to maximally 60 min after ejaculation. The W H O has recommended a minimal value of 13 p~ ( 1.2 mg ml- I ) - and an average value of 2.4 mg ml-I. When low values are interpreted, it has to be kept in mind that under circumstances a n increased fructolysis is more likely rather than diminished function of seminal vesicle epithelium. (6) Fructose glucose ratio: studying the ratio of glucose and fructose in liquefied seminal samples Montagnon and collaborators (1990) found a positive correlation only if the fructose values were below 1.2 mg ml-I. Above this value the glucose value remained constant at about 1.8 mg ml-'. Therefore, the authors hypothesize a prostate-derived factor which is responsible for the conversion of fructose into glucose. Glucose is not found in fresh ejaculates and increases during liquefaction time up to 45 min after ejaculation. The final values do not change anymore. Whereas fructose is non-dialysable immediately after ejaculation, it can be dialysed after liquefaction of the sample. Montagnon et a1 (1990) found two proteins (N3,N4) in seminal vesicle secretion which they made responsible for fructose binding. I n addition, it is suggested that these proteins participate in coagulation and liquefaction of seminal plasma. Glucose forming during this process initiated by prostatic secretion is thought to participate in energy supply spermatozoa. (7) Phospholipids. Montagnon and co-workers (1990) have studied the distribution of triglycerides, cholesterol and phospholipids in three different fractions of split ejaculates. I n the third fraction which represents the seminal vesicle secretion, they found: (a) 0.1 mg ml-' triglycerides, (b) 0.02 mg ml-l cholesterol, and (c) 4.05 mg ml- I phospholipids. Therefore, seminal vesicles seem to be responsible for the production of phospholipids found in seminal plasma. The prevalent sphingomyelin has a membrane stabilizing effect, and therefore, may be regarded as a decapacitation factor and is an antagonist to the capacitation protein (see below). The content in phospholipids of an average ejaculate amounts to 0.3 mg ml-' and distributes equally to spermatozoa and seminal plasma. In seminal plasma the prevalent phospholipids are phosphatidylserin and sphingomyelin 6.0 pg ml-', 77.0 pg ml-l (Nissen & Kreysel, ANDROLOGIA 24, 183-196 (1992)

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1988), whereas in spermatozoa phosphatidylcholin and phosphatidylethanolamin are found preferentially.

Peptides Among the several small peptides (Mann & Lutwak-Mann, 1981) of seminal plasma, most seem to be derived from epididymis or seminal vesicles.

( 1 ) Glutathion. This is found a t low amounts (below 2 p ~ and, ) it is suggested, protects spermatozoa against spermicidal intermediates of polyamine degredation. According to Polak & Daunter (1989) there is a complex correlation between L-ascorbic acid, glutathion, and spermine which is also influential on semen liquefaction. (2) P-endorphin. This is derived from the precursor molecule pro-opio-melano-cortin (POMC) and is found at relatively high concentrations in human semen. Chang & Tang (1984) found 326.3 & 14.2 pg ml-' in fertile and somewhat higher values in infertile men. In addition to the seminal vesicles, the prostate also seems to be involved in Pendorphin production. Since spermatazoa have a P-endorphin receptor, an influence of P-endorphin on sperm motility is conceivable. Proleins Study of seminal vesicle proteins has attracted increased interest during the last few years and a number of important new results have been published (for review, see Aumuller & Seitz, 1990; Shivaji et al., 1990). Basically, the following forms of proteins have to be distinguished: (1) Transport proteins and plasma analogues, (2) Structural proteins, (3) Sperm-modulating proteins, (4) Immuno-modulating proteins, (5) Enzymes, (6) Enzyme inhibitors

protein

Some proteins are multifunctional, i.e. they are simultaneously structural proteins and spermmodulating proteins or transport- and immunomodulating proteins. ( 1) Transport-proteins and plasmaprotein analogues: (a) Transferrin. Seminal transferrin is essentially derived from Sertoli cells. After vasectomy the value decreases to 20% of the initial value. The protein has a molecular rate of 78 kDa and isoforms with pI-values ranging between 5.2 and 6.2 have been described

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(Oratore et al., 1987). Seminal and plasma transferrin are closely related. However, they show some characteristic differences. (b) Lactoferrin. Lactoferrin is an iron-binding protein that is found in seminal plasma a t concentrations between 0.2 and 1.18 mg mlI n addition to iron it can bind a number of different other metal ions. Iron-binding capacity has been related to its bacteriostatic effects. By modulating of the complement system. Enhancement of NK-activity of monocytes and regulation of lymphoblastic, macrophage and granulocytic proliferation, lactoferin is most important immunomodulator in seminal plasma. Wichmann and co-workers ( 1989) have localized lactoferrin immunoreactivity, both in prostatic and seminal vesicle epithelium. I t has initially been described as a sperm binding protein and has been given the name ‘sperm coating antigen’ (SCA) which has later been described as ‘scaferrin’. According to Wichmann et al. (1989) lactoferrin could be responsible for the immunotolerance of the endometrium against spermatazoa before and after fertilization, the immunologically effected sperm immobilization, and surface modification. Hence, the possibility of sperm sequestration by spermatophagy may be induced by lactoferrin. (c) Placental proteins Ranta et al. (1981), Wahlstrom et al. (1982) and Seppala et al. (1985) have pointed to the presence of pregnancy-specific or placental proteins in seminal plasma. PP5 is a placental protein in the molecular weight range of 36-42.5 kDa from the p globulin fraction which has a 20% carbohydrate proportion. It has antiplasminactivity and has been related to the invasiveness of the trophoblast. Immunohistochemically, it has been described in epithelium of the seminal vesicle and the ampulla of the vas deferens (Wahlstrom et al., 1982). I n seminal plasma it is found at concentrations ranging between 32 and 1000 ng mi-’. I n addition to PP5, the PP14 and the so-called pregnancy-associated plasmaprotein-A (PAPP-A) has been described, the latter also in the prostate (Seppala et al., 1985).

’.

(2) Structural proteins: During ejaculation a small volume of highly concentrated epididymal spermatozoa is mixed with the secretions of the accessory sex glands and in addition a certain proportion of about 10% transsudated plasma protein. The major proportion of the ejaculate is

transformed into a viscous gel, that normally liquefies in 20 min. During this process preferentially the seminal vesicle-derived ‘semenogelin’ and fibronectin are involved as the essential structural proteins as well as the serin-protease prostate-specific-antigen which is derived from the prostate and is responsible for semen liquefaction. I n addition, perhaps a number of different components participate in the process of semen coagulation and liquefaction (Montagnon et al., 1990; Polak & Daunter, 1989). (a) Semenogelin. Semenogelin (for review, see Lilja, 1990) and the corresponding MHS-5 antigen (for review see Flickinger et al., 1990) has been identified as the most prevalent protein present in human seminal vesicle secretion. I t is responsible for the coagulation of semen. Subsequent to SDS-polyacrylamidegelectrophoresis (SDS-PAGE) it can be identified as a dominant band in the molecular weight range of 52 kD. I n native secretion after coagulation, it is found as a high molecular weight complex formed by several disulphide bonds, in which proteins a t the molecular weight of 7 1 and 76 kDa are prevalent (Fig. 15). These proteins can be identified with the monoclonal antibody MHS-5. (b) Proteolytic degradation. During liquefaction of semen, semenogelin protein are degraded into smaller subunits. Proteases derived from prostatic secretion are responsible for the degradation. The predominant enzyme is a kallikrein-like serine-protease ( M W 33 kDa) which has been described as prostate-specificantigen (PSA). Semenogelin, semenogelinlike proteins 71 and 76 as well as fibronectin have been identified as seminal substrates of PSA. Proteolytic degradation of the gelforming proteins within the 1 h produce a

Coomassie blue kDa Mr SP

Western blot kDa Mr 1 2 kDa

- -220 96 67-

=76/71 -52

46 29-

a

14-

b14-

I

15

Figure 15. Pattern of seminal vesicle proteins. a. SDS-PAGE and Coomassie stain. The left lane shows the molecular weight marker proteins. b. Western blot of semenogelin (1) and fibronectin (2) in the third fraction the split ejaculate that has been directly released into sample buffer containing protease inhibitors. ANDROLOGIA 24, 183-196 (1992)

HUMAN SEMINAL VESICLE: MORPHOLOGY

fragment pattern that can be identified by Western blotting using the MHS-5-antibody and consists of peptides ranging between 8 and 69 kDa of molecular weight. Fifteen hours after liquefaction, the immunoreactive bands are observed a t 10, 11.9, and 13.7 kDa, i.e. in the same range as has been previously described by Lilja and his group ( 12.8 kDa) . (c) Localization. Herr and co-workers (Flickinger et al., 1990) have localized the respective antigen both a t the light and electroscopic levels (using their M H 5- antibody) inside the secretory granules of the human seminal vesicle. It is obviously synthesized in the usual manner. Lilja and co-workers (Lilja 1990) using an antibody against the 52 kDa protein found an immunoreactivity on ejaculated spermatozoa in the post-acrosomal region of the head, in the mid piece and on the tail. This is consistent with the findings of the group of Herr. (d) Structure of semenogelin. Lilja and co-workers (1989) have described the primary structure of semenogelin as deduced from the nucleotide-sequence of the cDNA coding for the semenogelin precursor. This consists of 461 amino acid residues including 23 amino acids encompassing the signal sequence. T h e processed protein consists of 439 amino acids and contains the high amount of glycin (13.7%) and histidin (7%), but no methionin. Repetitive amino acid sequences occur. One cyste in residue in the position 2 16 is obviously responsible for the formation of homo dinners. The presence of carbohydrate side-chains is not definitely clarified yet (Lilja, 1990). (e) Physiological significance. Semenogelin related epitopes on human spermatozoa are in favour of a participation in the regulation of sperm motility. A more or less complete immobilization of spermatozoa could result in a trapping of sperms in the gel structure which is formed immediately after ejaculation by the mixture of glandular secretions. Liquefaction of the gel by PSA which is accompanied with a progressive fragmentation of semenogelin and the 71 and 76 kDa-proteins, that would result in a liberation and increasing mobility of the spematozoa which could be induced by low molecular weight fragments of semenogelin (Lilja 1990). (f) Fibronectin. Fibronectins (FN) are partly soluble, partly fixed glycoproteins which have a significance in cell adhesion (occurence in the basement membrane, on the surface of connective tissue cells and in serum). They ANDROLOGIA 24, 183-196 (1992)

AND FUNCTIONS

193

consist of two similar subunits which are connected by disulphide bonds (molecular weight 225-250 kDa). I n human seminal plasma fibronectins are found at a concentration of about 1 mg ml-'. This high concentration is in favour for an active secretion (Lilja et al., 1987). Fibronectin immunoreactivity is also observed on human spermatozoa. As deduced from secretions derived from men with agenesis of the seminal vesicles (Lilja et al., 1987) have identified seminal vesicles as the source for fibronectins. According to these fibronectin is incorporated into the semenogelin-derived coagulate (whereas lactoferrin remains soluble) and subsequently during liquefaction it is liberated by PSA. Therefore, fibronectin as well as semenogelin are substrates for PSA. T h e incorporation of fibronectin into the coagulum is not definitely clarified yet. (3) Sperm-modulating proteins (a) Sperm coating antigen (SCA). There is nearly unanimosity that sperm coating antigen (SCA) is identical with lactoferrin and scaferrin, respectively (Wichman et al., 1989). (b) Sperm binding protein. Abrescia et al. (1985) have used an antiserum against the rat seminal vesicle-derived protein SVS IV which is synthesised in the rat seminal vesicle in a testosterone-dependent manner. They found a cross-reactive protein in human seminal plasma and on human spermatozoa which they have termed sperm binding protein (SBP). Contrary to SVS IV (molecular weight 17 kDa) they found a molecular weight of 140 kDa for SBP. The authors suggest that this represents an aggregation product that is formed by the action of the seminal transglutiminase. Own unpublished studies using an SVS IV antibody have failed to get a clear cut positive immunoreaction in human seminal vesicle epithelium. (c) Seminal plasma motility inhibitor (SPMI). De Lamirande & Gagnon (1984) have described relatively high concentrations of a factor in secretion from seminal vesicles of bull, rat, and rabbit, that inhibits the motility of de membranated spermatozoa. (d) Structure. Iwamoto & Gagnon (1988a) have enriched this factor about 290 times from human seminal plasma and characterized more precisely. Molecular weight under native conditions ranges between 13 and 15 kDa and after SDS-PAGE at around 18-22 kDa. The isoelectric point (PI)is 9.1.

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The peptide is stable in a p H range between 5 and 10 and resists temperatures up to 60 "C. The factor inhibits the dynein-ATPase from bull spermatozoa in a concentrationdependent manner. (e) Function. According to Iwamoto & Gagnon (1988b), motility of intact and demembranated human spermatozoa is inhibited in the presence of 1600 pm ml- of SPMI. Velocity and speed frequency but not linearity of sperm motility are inhibited in a time dependent manner with increasing SPMI concentrations. Addition of seminal plasma increases these effects. Clinical studies performed by Gagnon and collaborators trying to find a correlation between SPMI concentration in seminal plasma and sperm motility in patients with asthenospermic were inconclusive as yet. Magnus et al., (1991) deny a specific regulatory effect of seminal plasma on sperm motility. ( f ) Antfertility protein. Zaneveld and his group (see Audhya et al., 1987) have described socalled antifertility proteins in seminal plasma, including an acrosin-inhibitor and an additional so called decapacitation factor (DF). Audhya et la. (1987) have elaborated purification method for this protein from human seminal plasma. ( 9 ) Structure. AF-I is a glycoprotein and has a molecular weight of about 200 kDa, consisting of two subunits of 125 and 72 kDa. Amino acid analysis showed high proportions of asparagin and glutaminic acid as well as leucine and serine whereas few tryptophan residues were present and methionin was absent. The carbohydrate fraction contained high amounts of galactose and acetylgalactosamin as well as mannose and N-acetylglucosamin and few residues of fucose and sialic acid. The high amount of carbohydrates seems to be responsible for the strong binding of the protein to the sperm surface. (h) Function. The factor inhibits with 50% efficiency at a protein concentration of 45 pg the penetration of capacitated mouse sperm through egg investments (follicular epithelium and zona pellucida). This function is related to the protein but not to the carbohydrate portion of the ,molecule. Neither sperm motility nor acrosome reaction are influenced by the factor. The factor can not be removed from sperm surface by simple washing procedures. Treatment of spermatozoa with capacitation medium, however, abolishes the effect of AF-1. Therefore, this has a reversable decapacitation function. Its

'

production in seminal vesicle is not yet established. (i) Gossact. Studying the inhibitory influence of gossypol, a well known antifertility factor on lactatdehydrogenase activity in human sperm, Nakamura et al. (1991) found a factor in seminal plasma that antagonizes gossypol activity. This protein has been named 'gossact' and has a molecular weight of 16 kDa and is present in a very low concentration of seminal plasma. The site of synthesis is not yet clear.

(4) Immuno-modulating proteins Antibacterial substances in seminal plasma are low molecular products of the prostate such as zinc, spermine, spermidine, and presumably also prostaglandins from seminal vesicle. A protein with bacteriolytic properties is seminalplasmin (see Shivaji et al. 1990), which has been described in the seminal vesicle of the bull, but not human seminal vesicle. The relatively high incidence of tumours in the male genital system, the role of the seminal plasma during AIDS transmission and the rather frequent inflammations in male genital tract point to an immodulating function of seminal plasma. However, no definite picture has been achieved yet (for reviews see Aumiiller & Seitz, 1990). Among the proteins of the seminal vesicle, that are a t present discussed as inhibitors of NK cell activity (Marcus el al., 1987), a seminal transglutaminase, the pregnancy associated protein A, or a 94-kDa-Fc-receptor-binding protein could play a major role. (a) Scaferrin (Lactoferrin). Due to its iron binding capacity lactoferrin has a bacterio static activity. I n addition, it is suggested that it modulates the C3-convertase of the compliment system, the activity of the monocytic natural killer cells, and inhibits the antibody cellular cytotoxicity (ADCC). Moreover, it is suggested that a number of monocyte functions are regulated by lactoferrin (receptor binding, opsonisation, phagocytosis, migration, proliferation, for details see Wichmann et al. [1989]).

( 5 )E n q m e s (a) Carboanhydrase ( C A ) : different isoforms of the enzymes are known. Their function consists in a reversible hydration of carbon dioxide, hence the regulation of electrolyte and acidbase metabolism, and the production of H + and HC03T-ions. Kaunisto et al. (1990) have ANDROLOGIA 24, 183-196 (1992)

HUMAN SEMINAL VESICLE: MORPHOLOGY

enzyme I1 in distal vas deferens, ampulla of the vas deferens, and in the seminal vesicle epithelium. This suggests that it is responsible for the regulation of bicarbonate concentration of seminal plasma. Okamura et al. ( 1985) have found a bicarbonate-sensitive adenylate cyclase system in sperm membranes that regulates sperm motility. They have shown that the required bicarbonates are synthesized in seminal vesicles. Hence, the androgen dependent synthesized carboanhydrase I1 of the seminal vesicle plays an important role in motility regulation of spermatozoa.

WAcetylglucosaminidase (hexosaminidase): Kapur & Gupta (1988) have demonstrated the presence of this enzyme in testicular Sertoli cells, epididymis, and in seminal vesicle epithelium. It therefore is not tissues specific. S'Nucleotidase: 5'nucleotidase is present in seminal vesicle of the bull as an 160 kDa protein, hydrolyzing AMP preferentially. A similar enzyme is also described in human seminal plasma (Fini, personal communication). An antibody directed against bull seminal 5'nucleotidase also stains spermbound enzyme on the acrosome of human spermatozoa (Aumuller, unpublished observation). Enqme inhibitors Whereas a series of peptides and respective inhibitors were found in seminal vesicles of domestic animals (bull, pig, stallion, see Aumuller & Seitz, 1990; Shivaji et al., 1990), in human seminal plasma only one inhibitor of a protein kinase has been found to date (Freedman & Kopf, 1985). CAMP-dependent or independent proteinases in human spermatozoa have been related to a number of sperm functions, especially motility. It is unknown, however, if the high molecular protein kinase inhibitor described by Freedman & Kopf (1985) has a regulatory function on sperm motility and where it is produced.

Conclusion Among the several proteins from human seminal vesicles presumably only a few are of clinical significance: (1) Semenogelin (in conjunction with fibronectin) is the essential structural protein of semen coagulation and liquefaction and its fragANDROLOGIA 24, 183-196 (1992)

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195

ments have perhaps motility regulating functions. (2) Lactoferrin is a bacteriostatic and immunomodulating factor. (3) Carboanhydrase and SPMI act as regulatory factors of sperm motility.

Acknowledgement The authors gratefully acknowledge the technical help of Dr B. Friedrichs, Mrs C. Keppler, Mrs I. Dammshauser and M r M. Dreher. Particular thanks are due to Mrs Gabriella Nicholls who typed the manuscript.

References Aboul-Azm TE (1979) Anatomy of the human seminal vesicles and ejaculatory ducts. Arch Androl 3:287-292. Abrescia P, Lombardi G, de Rosa M, Quagliozzi L, Guardiola J, Metafora S (1985) Identification and preliminary characterization of a sperm-binding protein in normal human semen. J Reprod Fertil 73:71-77. Audhya T, Reddy J, Zaneveld LJD (1987) Purification and partial chemical characterization of a glycoprotein with antifertility activity from human seminal plasma. Biol Reprod 36:5 1 1-52 1. Aumiiller G (1979) Prostate gland and seminal vesicles. In: Handbuch der mikroskopischen Anatomie des Menschen, Vol VII/6. Oksche A, Vollrath L, (eds) Springer, Berlin. Aumiiller G, Seitz J (1990) Protein secretion and secretory processes in male accessory sex glands. Int Rev Cytol 121 127-23 1. Aumiiller G, Jungblut T, Malek B, Konrad S, Weihe E (1989) Regional distribution of opioidergic nerves in human and canine prostates. Prostate 14:279-288. Balerna M, Medici G, Mazzucchelli L, Bianda T, Marossi L, Colpi GM (1990) Analytical biochemistry of seminal vesicle secretion: a challenge to andrological laboratories. andrologia 22, suppl 1 :166-1 77. Brewster SF (1985) The development and differentiation of human vesicles. J Anat 143:45-55. Chan SYW, Tang LHC (1984) Immunoreactive P-endorphin in human seminal plasma. IRCS Med Sci 12~622-623. Clavert A, Cranz C, Bollack C (1990) Functions of the seminal vesicle. andrologia 22, suppl. 1:185- 192. Colpi GM, Negri L, Mariani M, Balerna M (1990) Semen anomalies due to voiding defects of the ampullo-vesicular tract. Infertility due to ampullo-vesicular voiding defects. andrologia 22, suppl 1:206-2 18. Cossu M, Usai E, Sirigu P, Riva A (1978) Histochemical demonstration of glucose-6-phosphate dehydrogenase, D-sorbitol dehydrogenase, and alkaline phosphatase in human ampulla ductus deferentis. Fertil Steril 29~557-559. Cossu M, Marcello MF, Usai E, Testa Riva F, Riva A (1983) Fine structure of the epithelium of the human ejaculatory duct. Acta Anat 116:225-233. de Lamirande E, Gagnon C (1984) Origin of a motility inhibitor within the male reproductive tract. J Androl 5:269-276.

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Elbadawi A, Goodman DC (1980) Autonomic inncervation of accessory male genital glands. In: Male accessory sex glands, Spring-Mills E, Hafez ESE, (eds) Elsevier/North Holland, Amsterdam. pp 101-128. Flickinger CJ, Herr JC, McGee RS, Sigman M, Evans RJ, Sutherland WM, Summers TA, Spell DR, Conklin DJ (1990) Dynamics of a human vesicle specific protein. andrologia 22, suppl 1:142-154. Freedman MF, Kopf GS (1985) Characterization of a seminal plasma-associated inhibitor of human seminal plasma protein kinase. Biol Reprod 32:322-332. Holstein A-F (1978) Spermatophagy in the seminiferous tubules and excurretit ducts of the testis in rhesus monkey and in man. andrologia 10:331-352. Iwamoto T, Gagnon C (1988a) Purification and characterization of a sperm motility inhibitor in human seminal plasma J Androl 9:377-383. Iwamoto T, Gagnon C (198813) A human seminal plasma protein blocks the motility of human spermatozoa. J Urol 140:1045- 1048. Kapur DK, Gupta GS (1988) Immunocytochemical localization of p-N-acetyl glucosaminidase in human reproductive organs. Biol Reprod 38:373-376. Kaunisto K, Parkkila S , Tammela T, Ronnberg L, Rajaniemi H (1990) Immunohistochemical localization of carbonic anhydrase isoenzymes in the human male reproductive tract. Histochemistry 94:381-386. Kinghorn EM, Bate AS, Higgins SJ (1987) Growth of rat seminal vesicle epithelial cells in culture: Neurotransmitters are required for androgen-regulated synthesis of tissuespecific secretory proteins. Endocrinol 121:1678-1 688. Lilja H (1990) Cell biology of semenogelin. andrologia 22, suppl 1:132-141. Lilja H, Oldbring J, Rannevik G, Laurel1 C-B (1987) Seminal-vesicle secreted proteins and their reactions during gelation and liquefaction of human semen. J Clin Invest 80:281-285. Lilja H, Abrahamsson P-A, Lundwall A (1989) Semenogelin, the predominant protein in human semen. J Biol Chem 264: 1894-1900. Magnus 0, Brekke I, Abyholm T, Purvis K (1991) Effects of seminal plasma from normal and asthenozoospermic men on the progressive motility of washed human sperm. Int J Androl 14:44-51. Mann T, Lutwak-Mann C (1981) Male reproductive function and semen. Themes and trends in physiology, biochemistry and investigative andrology. Springer, Berlin. Marcus ZH, Lunenfeld B, Weissenberg R, Lewin LM (1987) Immunosuppressant material in human seminal fluid. Gynecol obstet Invest 23:54-59. Mata LR, Maunsbach AB (1982) Absorption of secretory protein by the epithelium of hamster seminal vesicle as studied by electron microscope autoradiography. Biol Cell 46:65-74. Montagnon D, Valtat B, Vignon F, Koll-Back MH (1990) Secretory proteins of human seminal vesicles and their relationship to lipids and sugars. andrologia 22, suppl 1 :193-205. Murakami M, Yokoyama R (1989) SEM observations of the male reproductive tract with special reference to epithelial phagocytosis. In: Developments in Ultrastructure of Reproduction, Motta PM (ed) AR Liss, New York. pp 207-2 14. Nakamura M, Ikeda M, Komukai M, Suyemitsu T, Okinaga S, Arai K (1991) Presence of a 16 kd protein in

human seminal plasma counteracts the effects of the antifertility agent, gossypol. Hum Reprod 6:7 14-721. Nissen HP, Kreysel HW (1988) Correlation between phospholipids and motility of human spermatozoa. In: Carl Schirren Symposium Advances in Andrology, Holstein AF, Leidenberger F, Holzer KH, Bettendorf G (eds) Diesbach, Berlin. pp 120-123. Okamura N, Tajima Y, Soejima A, Masuda H, Sugita Y (1985) Sodium bicarbonate in human seminal plasma stimulates the motility of mammalian spermatozoa through direct activation of adenylate cyclase. J Biol Chem 260:9699-9705. Oratore A, d’Alessandro A, Santiemma V (1987) Isolation and partial characterization of transferrin in human seminal fluid. Cell Mol Biol 33:593-599. Polak B, Daunter B (1989) Seminal plasma biochemistry. IV: enzymes involved in the liquefaction of human seminal plasma. Int J Androl 12:187-194. Ranta T, Siiteri JE, Koistinen R (1981) Human seminal plasma contains a protein that shares physicochemical and immunochemical properties with placental protein 5 from the human placenta. J Clin Endocrinol Metab 53: 1087-1089. Riva A, Cossu M, Usai E, Testa-Riva F (1981) Spermatophagy by epithelial cells of the seminal vesicle and of the ampulla ductus in man: A scanning and transmission EM study. In: Oligozoospermia: Recent Progress in Andrology. G. Frajese (ed) Raven Press, New York, pp. 45-53. Riva A, Testa-Riva F, Usai E, Cossu M (1982) The Ampulla ductus deferentis in man, as viewed by SEM and ?’EM. Arch Androl 8:157-164. Riva A, Usai E, Scarpa R, Cossu M, Lantini MS (1989) Fine structure of the accessory glands of the human male genital tract. In: Developments in Ultrastructure of Reproduciton, Motta PM (ed) AR Liss, New York. pp 233-240. Seppala M, Koskimies AI, Tenhunen A (1985) Pregnancy proteins in seminal plasma, seminal vesicles, preovulatory follicular fluid, and ovary. Ann NY Acad Sci 442:213-226. Shalev M, Frisch D, Hoffer A (1983) Comparative morphology of the vas and ampulla of many mammals. J. Androl 4:58 no. L34, abstract. Shan L-X, Rodriguez MC, Janne OA (1990) Regulation of androgenreceptor protein and mRNA concentrations by androgens in rat ventral prostate and seminal vesicles and in human hepatoma cells. Molec Endocrinol4: 1636-1646. Shivaji S, Scheit K-H, Bhargava PM (1990) Proteins of seminal plasma. Wiley, New York. Sirigu P, Cossu M, Scarpa R, Pinna A (1981) Histochemistry of some steroid-dehydrogenases in epithelia of human seminal vesicle, deferential ampulla, and prostate gland. Arch Androl 7:9-13. Tanaka T, Takeuchi T, Oguchi K, Niwa K, Mori H (1987) Primary adenocarcinoma of the seminal vesicle. Hum Pathol 18:200-202. Wahlstrom T, Bohn H, Seppala M (1982) Immunohistochemical demonstration of placental protein 5 (PP5)-like material in the seminal vesicle and the ampullar part of vas deferens. Life Sci 31:2723-2725. Weidner W (1991) Krankheiten der Blaschendriise. In: Andrologie, Krause W, Rothauge C-F (eds) F Enke, Stuttgart. pp 189-193. Wichmann L, Vaalasti A, Vaalasti T, Tuohimaa P (1989) Localization of lactoferrin the male reproductive tract. Int J Androl 12:179-186.

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