Maintenance of spermatogenesis and seminal vesicles in the hypophysectomized catfish, Heteropneustes fossilis (Bloch): effects of ovine and salmon gonadotropin, and testosterone.

Maintenance of spermatogenesis and seminal vesicles in the hypophysectomized catfish, Heteropneustes fossilis (Bloch): effects of ovine and salmon gonadotropin, and testosterone1 Department of Zoology, University of Delhi, Delhi 110007, India

Can. J. Zool. 1976.54:285-292. Downloaded from www.nrcresearchpress.com by Calif Dig Lib - Davis on 12/26/14. For personal use only.

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Wesf Vancouver Laboratory, Fisheries and Marine Service, 4160 Marine Drive, West Vancouver, British Columbia V7V 1N6 Received August 8 , 1975 NAYYAR, S. K., P. KESHAVANATH, B . I. SUNDARARAJ, and E. M. DONALDSON. 1976. Maintenance of spermatogenesis and seminal vesicles in the hypophysectomized catfish, Heteropneustes fossilis (Bloch): effects of ovine and salmon gonadotropin, and testosterone. Can. J. Zool. 54: 285-292. The effects of 20-day treatment with w i n e Iuteinizing (LH)and follicle-stimulating hormone (FSH), partially purified salmongonadotropin [SG-G 100). and testosterone were investigated by evaluating the maintenance ol'spermatu~enesisin the testes and secretory activity in the seminal vesiclt?~of the catfish, H ~ t ~ r u p n ~ r t s r r . r . f ~ ~ s safter i l i s .hypophy sectomy during the prespawning perid. Low doses oFLH (0.1 or 1 pg per fish) neither maintained spermatogenesis in the testes nor secretary activity in the seminal vesicies. whereas a higher dose of LH (10 gg per fish) maintained spermatogenesis qt~alitatively.and sustained the seminal vesicles in a moderately secretory state. One microgram of SG-G100per fish partially maintained spermatogenesis but the seminal vesicles showed p w r maintenance, Ten micrograms of SG-GlM per fish not only su~tainedspermatogenesis qualitatively and quantitatively. hut also induced sperrniation: the seminal vesicles. though enlarged. contained little secretion, indicating possible reduction through sperrniation. FSll did not maintain spermatopencsis in the te5tes or secretory activity in the seminal vesicles. Testosrerune ( 10.100, or500 p.g per fish) had adose-dependent maintenance response in the te4tes and seminal vesicles: with S(H) pgof rcstosterone the maintenance of testes and seminal vesicles was similar ro that ininitial inract controls. with noindication of spermiation. NAYYAR,S. K., P. KESHAVANATH, B. I. S U N D A R A Wet E. M. DONALDSON.1976. Maintenance of spermatogenesis and seminal vesicles in the hypophysectomized catfish, Neteropner~stesfossilis (Bloch): effects of ovine and salmon gonadotropin, and testosterone. Can. J. Zool. 54: 285-292. On a examine, chez le poisson-chat Herrropn~rtar~s fo.ssilis. les effets d'un traitement de 20 j o u r ~iI'hormone luteinisante d'ovidi (LH), i I'hormone stimultrice des rollicules IFSH), a la gonadotropine (SG-G100) pnrttellernent puriAee de snumon et i la teqtosterone, traitement a d m i n i s ~ kaprks I'ahfation de la ~ l a n d pituiraire e durant la pPriMle qui precede lafraye. Les e f f e t ~ drl traitemenr oat ete etudiis par Cvaluationde I'intensitedc la .rpermatogenese dans letesticule et de I'activite cicrktrice de\ vtr~culessiminale~.k r doses hibles d'hormone lutkin~sante(0.1 ou I pg par wissonl ne pemertent pa< la continuation de la rpermntogenese dans les testicules ni I'act iviti 3cretrlce dans les v i s ~ c t ~ lsPminales, es alors qu'une dose plus forte ( 10 ~g parpoi?sonl rii~ssita maintenir qualitnrivcmenr la spermatopenew et permet aux v~siculesseminalcs de secrkter modecement. U n micrornamme de SG-GI00 par poisson maintient la spermatogenese, mais les visicules sirninales sicr'etent peu. Une dose de ldpgdde SG-G100par poissctn rnainrient qualitativement et quantitativemcnt la spermatogenkse el diclcnche mkme le passage du sperme dans les visicules [spermiatian,: les vecicules sirninales. hien que gonflees, contiennent p u de secrktion. probablement ir cause de la spermiation, t'hormone FSH ne maintient ni la spermalogenkse ni I'activite qecritrice des vesicules shminales. La rcnction des testicules et des v~sicules~Crninalesi la tesrostdrone (10, I(H1. 500 pg par poisson) dkpend de la dose: la dose de 500 fig maintient les testicules et les visicules seminnlesen un itat comparable acelui des temoins intacts, sans qu'il y ait indication de spermiation. p r a d u i t par le journal] 'Supported in part by research grant M69.91 from the Population Council, The Rockefeller University, New York, and research grant GF-34379 (to B.I.S.) from U.S. National Science Foundation, Washington, D.C.


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CAN. J. ZOOL. VOL. 54. 1976

Introduction Hypophysectomy brings about an interruption and eventual cessation of spermatogenic activity in the testes, as well as regression of the seminal vesicle secretory epithelium in the catfish, Het~ropneustesfossilis (Sundararaj and Nay yar 1967). Human chorionic gonadotropin (HCG), w i n e luteinizing hormone (LH), partially purified salmon gonadotropin (SG-G IOQ), and testosterone not only reinitiate spermatogenesis in the fully regressed testes, but also induce secretory activity in the atrophic seminal vesicles o f long-term hypophysectomized catfish (Sundararaj and Nayyar 1967; Sundararaj et al. 1971); ovine fol ticlt-stirnula ting lrormone (FSH), however, is ineffective (Sundararaj and Nayyar 1967). The hormonal requirements for maintenance of spermatogenesis in the testes and secretory activity in the seminal vesicles of the catfish have not been investigated. The present study evaluated the relative potencies of ovine LH, FSH, SG-G100, and testosterone in maintaining spermatogenesis in the testes and secretory activity in the seminal vesicles of catfish during the prespawning period after hypophysectomy. Materials and Methods Adult specimens or Har~ropneusr~s fu$si!is were mllmted and maintained as described in previous papers (Sundararaj and Nayyar 1967; Sundararaj et 01. 1971). Two experiments were perFormed during the prespawning period (May-June). Catfish were hypophysectomized by the technique or Sundararaj and Goswami (1965), and treatment w ~ t hhormones was started the day after hypophysectomy and continued f o ~20 days. The groups and the daily dosages of the hormones uscd are shown in Figs. 1 and 2. The trmted catfish were sacrificed on the day after the last injection. They were weighed to rhe nearest pram and immediately killed by decrapltation. The testes and seminal vesicles were carerully dissetfed oul, weighed to the nearest 0.5 mg on a torsion balance, and fixed in formol -ethanol -acetic acid o r Rouin's fixative for subsequent histological examination. Transverse 5ections of thc testes and seminal vesicles were cut at Sprn and stained with Ehslich's haematoxylin and easin. At the rime of autopsy, the brain of each fish was carefully examined under magnification; a few catfish had evidence of pituitary remnants and they were discarded. Experiments were conducted in an air-conditioned laboratory where the temperature was kept at 25 5 1 "C, and the lighting schedule at IS h OF light (0800-2000 hours) and 12 h of darkness. The catFish were fed ad libitum on alternate days with New Age 5132in. pellets (M/s. MooreClark Company, Salt Lake City, Utah). The water in the aquaria was renewed daily. Aqueous solutions or suspensions of hormones were prepared in

0.6% sodium chloride solution. They were i n j d intramuscularly with a I-ml tuberculin syringe fitted with a 26-gauge needle; the volume administered was kept constant at 0.05 ml. Fresh solutions and suspensions were made weekIy. Fortified promine penicillin (Pronapen: Wber; 50 000unitsllitre) was added daily to the aquarium water as a prophylactic measure against skin infection. For comparison of data. all testes and seminal vesicle wights were calculated on the basis of a 100-g body weight. P values between the control and the experimental erouus were calculated bv the Student's t-test (Snedec-or T959j. The seminiferous iubulsr area and the germ-cell counts in transverse sections of seminiferous tubules were determined by the methods of Sundararaj and Nayyar (1967).

Results Experiment 1-Maintenance of Testes and Seminal Vesicles in Hypophysectomized Catfish with Ovine Luteinizing Hormone (LH) and Salmon Gonadotropin (SG-G100) Initial Intact Control The testes were active (Fig. 1) and the seminiferous tubules contained all stages of spermatogenesis with plenty of spermatozoa in the lumina (see Table 1, group 1). The area of the seminiferous tubules was 11.33 mm2. Leydig cells were active and secretory. The seminal vesicles were enlarged and secretory. Saline-treated Hypophysectomized Control The testes were significantly (P < 0.001) regressed (Fig. 1). Histological examination revealed complete cessation of spermatogenesis in the seminiferous tubules, and the predominant cell types were the spermatogonia and residual spermatozoa (Table 1, group 2). However, in two specimens some spermatocytes were noticed (Table 1, group 2). The intertubular connective tissue was thick and the Leydig cells were atrophic. The seminal vesicles too were significantly regressed (P < 0.001) and most of the loculi, though shrunk, contained moderate amounts of secretion. Treatment with LH LH at dose levels of 0.1 or 1 pg per fish failed to support the weights of testes and seminal vesicles (Fig. 1 ; compare with initial intact control). The seminiferous tubules had regressed and contained only spermatogonia and residual spermatozoa; spermatocytes and spermatids were absent in all except one specimen injected with 1 pg of LH; it had a few spermatocytes (Table 1, group 4). Leydig cells and seminal vesicles had regressed. The testes of catfish receiving 10 pg of LH were maintained only quali-

287

NAYYAR ET AL.: HORMONES AND SPERMATOGENESIS IN CATFISH

L

: *

I-

I

z w

I

&

500

NUMBER

OF

MEAN t

sE

CATFISH

OF

MEAN

350

&

9,400

SEMINAL

0-

VESICLES

0

300 0 2= 0-

0

9

250 2

% 300

I-

-

I


E

200

I-

I

z3 Y

150 '

200

2 52 so 5

3

W

k2

I00 I00

I-

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Ln

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8

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INITIAL INTACT CONTROL

HYPECT SALINE CONTROL

HYPECT LH 04/19

HYPECT LH I f i g

.

HYPECT LH 1 0 p g

HYPECT SG-G 100 0-lA9

HYPECT SG-G 100 1 p9

HYPECT St-GI00 10 P9

T

W

.x

FIG.1. Maintenance of testes and seminal vesicles in the hypophysectomized (Hypect.) catfish, Heteropneustes fossilis, with ovine luteinizing hormone (LH: NIH-LH-S16, 1.09 NIH unitslmg or 1676.4 IU/mg) and salmon gonadotropin (SG-G100) during the prespawning period (May). The mean body weights of the groups from left to right were 34.7,20.2, 32.4,27.0, 37.3, 37.6,32.0, and 32.0 g. P values calculated by Student's t-test for testicular weights between initial intact control and hypophysectomized saline control: P < 0.001; initial intact control and hypophysectomized LH 0.1, 1, and 10 pg: P < 0.001,0.01, and 0.001 respectively; initial intact control and hypophysectomized SG-GI00 0.1 and 1 pg: P < 0.001 and 0.01 respectively. P values for seminal vesicle weights between initial intact control and saline-treated hypophysectomized control: P < 0.001 ; initial intact control and hypophysectomized LH 0.1 and 1 pg and SG-GI00 0.1 pg: P < 0.001, 0.01, and 0.001 respectively.

tatively (see Table 1, group 5), in that all stages of spermatogenesis were present. The interstitial cells were also maintained in a moderately active state. The seminal-vesicle weights were sustained and they were comparable with those of the initial intact catfish. The loculi contained moderate to abundant secretion. Treatment with SG-GI00 Treatment with 0.1 pg SG-GI00 per fish could not maintain testicular weights (Fig. I), and sustained only marginal spermatogenesis in the testes (see Table 1, group 6). Leydig cells were partially maintained. The seminal-vesicle weights were also not sustained; they resembled those of saline-treated hypophysectomized fish. The testes of the catfish injected with 1 pg were partially maintained (see Fig. 1) and the seminiferous tubules contained all stages of spermatogenesis (see Table 1, group 7). Leydig cells were maintained in an active state. Seminalvesicle weights were supported as well; they were

comparable with those of the initial intact control fish. Catfish injected with 10 pg had wellmaintained testes (Fig. 1) and spermatogenesis was sustained both qualitatively and quantitatively (see Table 1 ; compare groups 1 and 8). A decrease in the abundance of spermatozoa indicated possible spermiation. Leydig cells were in a secretory state. The seminal vesicles were well maintained and their loculi, though distended, had little secretion, which indicated once again a possible decrease through spermiation. Experiment 2-Maintenance of Testes and Seminal Vesicles in Hypophysectomized Catjish with Ovine Follicle-stimulating Hormone (FSH) and Testosterone Initial Intact and Saline-injected Hypophysectomized Controls The testes and seminal vesicles of the initial intact and saline-injected hypophysectornized controls resembled the corresponding groups in

28s

CAN. J. ZOOL. VOL. 54. 1976

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NUMBER OF CATFISH MEAN 2

sE

8

OF MEAN

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350

300

--f h


I-

250

5

200

,

5

2

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tso Q I00 50

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HYPECT SALINE CONTROL

HYPECT FSH 10pg

HYPECT HYPECT HYPECT HYPECT FSH 100pg TESTOZTERONE TESTO!XERONE TESTOSTERONE 100 P9 sOO,&3 10 &9

d r

FIG.2. Maintenance of testes and seminal vesicles in the hypophysectomized (Hypect.) catfish, Heteropneustesfossilis, with ovine follicle-stimulating hormone (FSH: NIH-FSH-S6, 1.24 N I H units/ mg or 32.9 1U/mg) and testosterone (Sigma Chemicals) during the prespawning period (June). The mean body weights of the groups from left to right were 33.7, 34.0, 34.2, 38.4, 32.8, 27.7, and 28.0 g. P values calculated by Student's t-test for testicular weights between initial intact control and hypophysectomized saline control: P < 0.001; initial intact control and hypophysectomized FSH 10 and 100 pg: P < 0.001; initial intact control and hypophysectomized testosterone 10 and 100 pg: P < 0.005 and 0.01 respectively. P values for seminal vesicle weights between initial intact control and hypophysectomized saline control: P < 0.005; initial intact control and hypophysectomized FSH 10 and 100 pg: P < 0.001 ; initial intact control and hypophysectomized testosterone 10 pg: P < 0.02.

experime.nt 1 in both weights and histology (compare Fig. 2 with Fig. I).

were not maintained (see Fig. 2). With the lowest dose (10 pg), the testes of only two of six specimens revealed a marginal maintenance, in that Treatment with FSH a few spermatocytes and spermatids (see Table At 10- and 100-pg dose levels, FSH did not support the weights and histology or the tmtes 2, group 5) were present. With 100 pg of testosand seminal vesicles. The predominant celt types terone the testicular weights and spermatogenein the seminiferous tubules were the sperma- sis were maintained. A higher dose of testostogonia and residual spermatozoa: however, one terone (500 pg) maintained the testicular weights fish in each group did show the presena of afew o f hypophysectomized catfish to the level of those in the initial intact group (see Fig. 'permatids 2, groups and 4)+ 2). Hirfo~ogically, the seminiferous tubules Leydig cells were not secretory. Most of the showed all stages of spermatogenesis (Table 2, loculi in the seminal vesicles were small and de7). The Leydig cells of testosterone-treated group void of secretion. catfish were not maintained. Treatment with Testosterone The seminal vesicles of testosterone-treated Catfish receiving 10, 100, or 500 pg testos- catfish also showed a dose-dependent mainteterone per fish showed a dose-dependent main- nance response (see Fig. 2). With 10 pg, even tenance response in the testes (Fig. 2). The testic- though the seminal-vesicle weights were signiular weights of catfish treated with 10 or 100 pg ficantly lower (P < 0.01) than those of the initial

289


TABLE 1. Effects of ovine luteinizing hormone (LH), and salmon gonadotropin (SG-G100) on germ cell population in seminiferous tubules of hypophysectomized (Hypect.) catfish, Heteropneustes fossilis


Group No.

20-day treatment and daily doses, pg

1

Initial intact control

2

Hypect. saline control

3

Hypect. LH 0.1

4

Hypect. LH 1 pg

5

Hypect. LH 10 ~g

6

Hypect. SG-G1OOO.l pg

7

Hypect. SG-G100 1 pg

8

Hypect. SG-GI00 10 pg

Mean area of seminiferous tubule cross section, mm2 x 400 11.33+0.81* (6) 4.03k0.44 (5) 5.17k1.12 (3) 4.31k0.36 (4) 8.40k0.50 (4) 3.23k0.31 (5) 4.86k1.32 (4) 9.54+ 1.18 (4)

Mean no. cells per tubule cross section Spermatogoniat

Spermatocytesj

18.5k1.7 102.7k9.2 (6) (6) 18.1 k 2 . 0 1.0k0.7 (5) (5) 16.5k4.3 (3) 12.3f 0.7 0.3k0.3 (4) (4) 29.5k5.1 61.9f9.2 (4) (4) 22.1_+1.1 1.7k1.4 (5) (5) 32.0k7.2 10.7f3.8 (4) (4) 47.4k3.0 98.9f 14.0 (4) (4)

Spermatids5

Spermatozoa

232.2k28.4 (6)

+++I1

-

157.3k58.4 (4) 4.4k4.0 (5) 12.0+11.4 (4) 196.9k17.6 (4)

+++ +++ +++ +++ +++ +++ ++

'Mean ? SE of mean. Figures in parentheses indicate number of catfish. tIncludes primary and secondary spermatogonia. $Includes primary spermatocytes in various phases of meiosis. §Includes fully formed spermatids as well as those undergo~ngspermateliosis. IlArbitrary units indicating moderate (+ +) to abundant ( + +).

+

intact controls, some loculi were distended and packed with secretion. The seminal vesicles in the catfish treated with 100 or 500 pg of testosterone showed a good maintenance response and they were comparable with those of initial intact controls. Discussion In the catfish, the activities of the testes and seminal vesicles are regulated by the hypophysial secretions, since their withdrawal, after hypophysectomy, leads to disruption and arrest of spermatogenesis in the testes, and the involution of secretory activity in the seminal vesicles. These observations are consistent with the findings reported earlier for the catfish, H. fossilis (Sundararaj and Nayyar 1967 ; Sundararaj et al. 1971 ; Sundararaj and Anand 1972), and for other teleost fishes (see reviews: Pickford and Atz 1957; Dodd 1960; Hoar 1965, 1969; Lofts 1968 ; Donaldson 1973). In the hypophysectomized catfish, of the three gonadotropins used (LH, FSH, and SG-G 100), SG-G 100 (10 pgj was the most potent gonadotropin for maintaining spermatogenesis in the testes and secretory activity in the seminal vesi-

cles. The hormonal requirement for maintenance of spermatogenesis (10 t ~ g )appears to be much lower (about one-tenth) than that necessary for reinitiation of spermatogenesis (I00 pg) after long-term hypophysectomy (see Sundararaj ef a!. 197 1). In Gi/iiridys mirubifis, SG-G 100 prevents warm- (27 "C) temperature-induced testicurar regression (de Vlaming 1972, 1974). Billard and Escaffre (1973), in their studies on the hypophysectomized goldfish, have shown that carp gonadotropin maintains spermatogenesis. While there is unanimity of opinion with regard to the efficacy of piscine gonadotropins on piscine testes, there is controversy about the action of mammalian gonadotropins on piscine testes. The general consensus is that, while LH and HCG can reinitiate and maintain spermatogenesis in ttleost fishes, FSH has consistently given negative results (Ahsan and Hoar 1963; Ahsan 1966; Sundararaj and Nayyar 1967; Lofts 1968; Hoar 1969; Wiebe 1969; Hyder er al. 1970; Sundararaj et al. 1971 ; Pickford et a/. 1972; Bliirn 1972; Dadzie 1973). In the present study also, LH maintains spermatogenesis in the hypophysectomized catfish, whereas FSH is ineffective.

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CAN. J . ZOOL. VOL. 54, 1976

TABLE 2. Effects of ovine follicle-stimulating hormone (FSH), and testosterone (Testo.) on germ cell population in seminiferous tubules of hypophysectornized (Hypect.) catfish, Heteropneustesfossilis

Group No.

20-day treatment and daily doses, pg

1

Initial intact control

2

Hypect. saline control --

Mean area of seminiferous tubule cross section, mm2 x 400

Spermatogoniat

Spermatocytest

Spermatids8

Spermatozoa

8.08+1.00* (5) 3.49k0.21

14.6-11.0 (5) 11.9+ 1 . 7

66.6k7.9 (5)

180.7k17.2 (5)

++" +++

Mean no. cells per tubule cross section

-

-


(5)

3

Hypect. FSH 10 pg

5.14+0.09

5

Hypect. Testo. 10 pg

6


7


5.49-0.46 (6) 5.82k0.66 (6) 9.44 + 0.90 (5)

*Mean SE o f mean. Figures in parentheses indicate number o f catfish. tlncludes primary and secondary spermatogonia. $Includes primary spermatocytes in various phases o f meiosis. Blncludes fully formed spermatids as well as those undergoing spermateliosis IlArbitrary units indicating moderate ( + +) to abundant (+ +).

+

I n contrast to the above data, Billard er al. (5970) have failed to induce spermatogenesis in the testes of hypophysectornized goldfish, Curassfus alcratus, with ovine FSH and LH (Centre National d e la Recherche Scientifique), De Vlaming (1972, 39743 has reported that in hypoph ysectom ized Gillichrhja mirahilis HCG does not promote spermatogenesis at 16 and 25 'C, whereas in intact fish, ovine LH induces significant testicular weight increases and gonadal hydration at both 12 and 27 "C; but whether or not LH stimulates spermatogenesis is not clear from his data. Billard and Escaffre (1973) could not maintain spermatogenesis in the hypophysectomized goldfish with HCG. Breton et al. (1973) have reported that ovine LH, FSH, and HCG, at the dose levels used, neither maintained nor regenerated spermatogenesis in the hypophysectomized goldfish, Carassius auratus, or in the guppy, Poecilia reticulata. It is surprising lhat in the hypophgsectamized catfish, H. .fossilis, ovine EH and HCG can reinitiate spermatogenesis (Sundararaj and Nayyar 1967; Sundararaj et al. 19711, whereas they are incapable of doing so i n the goldfish (a carp (Cyprinidae) related to the catfish (Heteropneustidae)). This problem needs reexamination. In the present study, testosterone maintains

spermatogenesis in the testes as well as secretory activity in the seminal vesicles of hypophysectomized catfish. The relatively high dose of testosterone which was required to produce a significant response may have been related to the intramuscular injection site and to the possibility that the androgenic potency of testosterone is lower than that of the endogenous androgens in this species. In a study of the effect of androgen on the testis of Carassius auratus it was postulated that high doses of exogenous androgen were required to compensate for the fact that endogenous androgen is produced in close proximity to its site of action in the spermatogenic tissue of the testis (Yamazaki and Donaldson 1969). Burger (1 942) has, however, reported poor maintenance of spermatogenesis in the testes of hypophysectornized Fundulus after treatment with testosterone propionate. Dadzie (1973) has also stated that administration of 0.42 mg of testosterone propionate, injected six times per week for 30 days, to methallibure-treated intact male Tilapia aurea suppressed testicular weight and retarded spermatogenesis, but restored secondary sexual characters and spawning behaviour. The significance of these results is not clear. Since in the hypophysectornized testosterone-



29 1

and R. BILLARD.1973. PituBRETON,B., B. JALABERT, itary and plasma gonadotrophin levels and spermatogenesis in the goldfish Carassius auratus after methallibure treatment. J. Endocrinol. 59: 415420. BURGER,J. W. 1942. Some effects of androgens on the male adult Fundulus. Biol. Bull. Woods Hole, Mass. 82: 233-242. BURZAWA-GERARD, E., and Y. A. FONTAINE.1965. Activites biologiques d'un facteur hypophysaire gonadotrope purifie de poisson teleosteen. Gen. Comp. Endocrinol. 5: 87-95. -1966. Sur le probleme de I'unicite ou de la dualite de l'hormone gonadotrope hypophysaire d'un Teleosteen, la carpe. Etude du poids moltculaire de la ou des substances actives. Ann. Endocrinol. 27: 305-309. DADZIE,S. 1973. Effects of exogenous hormones on the pituitary gonadotrophic activity in Tilapia previously treated with a dithiocarbomoylhydrazine derivative (I.C.I. 33 828). Ghana J . Sci. 13: 20-34. DE VLAMING, V. L. 1972. The role of the endocrine system in temperature-controlled reproductive cycling in the estuarine gobiid fish, Gillichthys mirabilis. Comp. Biochem. Physiol. 41A: 697-713. 1974. Environmental and endocrine control of teleost reproduction. I n Control of sex in fishes. Edited by C . B. Schreck. Sea Grant Extension Division (VPI-SG-74-01), Virginia Polytechnic Institute and State University, Blacksburg, Virginia. pp. 13-83. DODD,J. M. 1960. Gonadal and gonadotrophic hormones in lower vertebrates. In Marshall's physiology of reproduction. 3rd ed. Vol. 1. Part 2. Edited by A. S. Parkes. Longmans, Green and Co., London. pp. 417-582. E. M. 1973. Reproductive endocrinology of DONALDSON, fishes. Am. Zool. 13: 909-927. 1968. Preparation DONALDSON, E. M., and F. YAMAZAKI. of gonadotropic hormone from salmon pituitary glands. 51st Ann. Conf. Chem. Inst. Can. p. 64. (Abstr.) Acknowledgment H. M. D ~ ~ , a W. n dW. DONALDSON, E. M., F. YAMAZAKI, PHILLEO.1972. Preparation of gonadotropin from salWe wish to express our appreciation to the mon (Onrorhynrhus rshawytscha) pituitary glands. Endocrinology Study Section, National Institute Gen. Comp. Endocrinol. 18: 469-481. of Health, Bethesda, Maryland, for supplying FONTAINE, Y. A., and E . GERARD.1963. Purification d'un LH-S-16 and FSH-S-6. facteur gonadotrope de I'hypophyse d'un Teleosteen, la carpe (Cyprinus carpio L.). C.R. Acad. Sci. 256: AHSAN,S. N. 1966. Effects of gonadotropic hormones o n , 5634-5637. HOAR,W. S. 1965. Comparative physiology: hormones male hypophysectomized lake chub, Couesius and reproductioninfishes. Ann. Rev. Physiol. 27: 51-70. plumbeus. Can. J . Zool. 44: 703-717. 1969. Reproduction. It1 Fish physiology. Vol. 111. AHSAN,S. N., and W. S. HOAR. 1963. Some effects of Edited by W. S. Hoar and D. J . Randall. Academic gonadotropic hormones on the threespine stickleback, Gasterosteus aculeatus. Can. J. Zool. 41: 1045-1053. Press, New York. pp. 1-72. BILLARD,R., E . BURZAWA-GERARD, and B. BRETON. HYDER,M., A. V. SHAH,and M. A. KIRSCHNER.1970. Effect of chorionic gonadotrophin on testicular histology 1970. Regeneration de la spermatogenese du Cyprin hypophysectomise (Carassius auratus L.) par unfacteur and testosterone production in Tilapia leucosticta gonadotrope hautement purifie de carpe. C.R. Acad. (Teleostei: Cichlidae). Endocrinology, 87: 819-822. Sci. 271: 1896-1899. LOFTS,B. 1968. Patterns of testicular activity. In PerspecBILLARD, R., and A. M. ESCAFFRE.1973. Effects of HCG tives in endocrinology. Edited by E. J. W. Barrington and carp gonadotropin on the maintenance of sperand C. B. Jgrgensen. Academic Press, London. pp. matogenesis in hypophysectomized goldfish (Carassius 239-304. auratus). IRCS Int. Res. Commun. Syst. PICKFORD, G. E., and J. W. ATZ. 1957. The physiology of BLUM,V. 1972. The influence of ovine follicle stimulating the oituitary- gland of fishes. N.Y. Zool. Soc., New hormone (FSH) and luteinizing hormone (LH) on the YO&. male reproductive system and the skin of the MediterraPICKFORD. G. E.. B. LOFTS, G. BARA,and J. W. ATZ. nean blenniid fish, Blennius sphinx (Valenciennes). J. 1972. Testis stimulation in hypophysectomized male Exp. Zool. 181: 203-216. killifish, Fundulus heteroclitus, treated with mammalian

treated catfish, the Leydig cells are atrophic, and because they are active in SG-G100- and LH-treated catfish, testosterone is possibly acting directly on the seminiferous tubules and seminal vesicles, whereas SG-GI00 and LH act through the Leydig cells and androgen production. This hypothesis is supported by the observation that in the hypophysectomized Fundulus heteroclitus, LH increases the activity of 3P-hydroxysteroid dehydrogenase in the Leydig cells, and thus promotes the synthesis of steroid hormones (Pickford et al. 1972). Of the two mammalian hypophysial gonadotropins (FSH and LH) used in this study, only LH mimics the physiological effects of piscine gonadotropin (SG-G100); FSH has no such effect. These findings are interesting because the recent biochemical and physiological evidence supports the tentative view that in teleost fish only one gonadotropin may regulate the whole maturational phenomenon (Fontaine and Gtrard 1963; Burzawa-Gtrard and Fontaine 1965, 1966; Donaldson and Yamazaki 1968; Yamazaki and Donaldson 1968a, 19686; Hoar 1969; Billard et al. 1970; Sundararaj et al. 1971 ; Sundararaj et al. 1972; Donaldson et al. 1972). Nonetheless, extrapolations and generalizations should be made cautiously until more teleost species are investigated and tested.


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growth hormone andlor luteinizing hormone. Biol. Re- SVNDARARAJ, B. I., S. K. NAYYAR, T. C. ANAND,and E. prod. 7: 370-386. M. DONALDSON.1971. Effects of salmon pituitary SNEDECOR, G. W. 1959. Statistical methods. Iowa State gonadotropin, ovine luteinizing hormone, and testosCollege Press, Ames, Iowa. terone on the testes and seminal vesicles of hypophysecSUNDARARAJ, B. I., and T. C. ANAND.1972. Effects of tomized catfish, Heteropneustes fossilis (Bloch). Gen. piscine and mammalian gonadotropins on gametoComp. Endocrinol. 17: 78-82. genesis in the catfish, Heteropneustes fossilis (Bloch). WIEBE,J . P. 1969. Endocrine controls of spermatogenesis Gen. Comp. Endocrinol. Suppl. 3: 688-702. and oogenesis in the viviparous seaperch, Cymatogaster and V. R. P. SINHA. SUNDARARAJ, B. I., T. C. ANAND, aggregata Gibbons. Gen. Comp. Endocrinol. 12: 1972. Effects of carp pituitary fractions of vitellogenesis, 267-275. ovarian maintenance, and ovulation in hypophysec- YAMAZAKI, F., and E. M. DONALDSON. 1968a. The spertomized catfish,Heteropneustes fossilis (Bloch). J. Enmiation of goldfish (Carassius auratus) as a bioassay for docrinol. 54: 87-98. salmon (Oncorhynchus tshawytscha) gonadotropin. 1965. 'Seminal SUNDARARAI, B. I.. and S. V. GOSWAMI. Gen. Comp. Endocrinol. 10: 383-391. vesicle' response of intact, castrate, and hypophysec19686. The effects of partially purified salmon tomized catfish, Heteropneustes fossilis (Bloch) to tespituitary gonadotropin on spermatogenesis, viteltosterone propionate, prolactin, and growth hormone. logenesis, andovulation in hypophysectomized goldfish, Gen. Comp. Endocrinol. 5: 464-474. Carassius auratus. Gen. Comp. Endocrinol. 11: SUNDARARAI, B. I., and S. K. NAYYAR. 1967. Effects of 292-299. exogenous gonadotrophins and gonadal hormones on 1969. Involvement of gonadotropin and steroid the testes and seminal vesicles of hypophysectomized hormones in the spermiation of the goldfish (Carassius catfish, Heteropneustes fossilis (Bloch). Gen. Comp. auratus). Gen. Comp. Endocrinol. 12: 491-497. Endocrinol. 8: 403-416.

Response of the pituitary of the catfish, Heteropneustes fossilis (Bloch), to bilateral ovariectomy.

Osmoregulation in the stenohaline freshwater catfish, Heteropneustes fossilis (Bloch) in deionized water.

Ameliorative stroke of selenium against toxicological effects of mercuric chloride in liver of freshwater catfish Heteropneustes fossilis (Bloch).

Malathion induced changes in the serum proteins and hematological parameters of an Indian catfish Heteropneustes fossilis (Bloch).

Effects of photoperiod alterations on day-night variations in hypothalamic serotonin content and turnover, and monoamine oxidase activity in the female catfish, Heteropneustes fossilis (Bloch).

Histopathological changes induced by acute toxicity of mercuric chloride on the epidermis of freshwater catfish--Heteropneustes fossilis (Bloch).

Impact of malathion and gamma-BHC on lipid metabolism in the freshwater female catfish, Heteropneustes fossilis.

Effects of melatonin, p-chlorophenylalanine, and α-methylparatyrosine on plasma gonadotropin level and ovarian activity in the catfish, Heteropneustes fossilis: A study correlating changes in hypothalamic monoamines.

Demonstration of putative thyroid hormone receptor in the brain nuclei of Singi fish, Heteropneustes fossilis (Bloch).

Ovarian activity, and total gonadotrophin and gonadotrophin releasing hormone levels in response to some synthetic non-steroidal ovulating agents in the catfish, Heteropneustes fossilis (Bloch).

Derivation and characterization of a ES-like cell line from indian catfish Heteropneustes fossilis blastulas.

Nerium indicum, a botanical pesticide affects ultimobranchial gland of the catfish Heteropneustes fossilis.

Impact of gamma-BHC on lipid class levels and their modulation by reproductive hormones in the freshwater catfish, Heteropneustes fossilis.

Changes in vasotocin levels in relation to ovarian development in the catfish Heteropneustes fossilis exposed to altered photoperiod and temperature.

In vitro demonstration of putative nuclear 3,5,3'-triiodothyronine receptors in isolated liver nuclei of Singi fish, Heteropneustes fossilis (Bloch).

Melanins as biomarkers of ovarian follicular atresia in the catfish Heteropneustes fossilis: biochemical and histochemical characterization, seasonal variation and hormone effects.

Alterations of ion-dependent ATPase activities in the brain of Singi fish, Heteropneustes fossilis (Bloch), by triiodothyronine.

Effects of ovaprim, a commercial spawning inducer, on vasotocin and steroid hormone profiles in the catfish Heteropneustes fossilis: in vivo and in vitro studies.

Molecular cloning and characterization of brain and ovarian cytochrome P450 aromatase genes in the catfish Heteropneustes fossilis: Sex, tissue and seasonal variation in, and effects of gonadotropin on gene expression.

Effects of testosterone and dihydrotestosterone on spermatogenesis, rete testis fluid, and peripheral androgen levels in hypophysectomized rats.

Molecular cloning, sequencing and phylogeny of vasotocin receptor genes in the air-breathing catfish Heteropneustes fossilis with sex dimorphic and seasonal variations in tissue expression.

Testosterone control of nucleic acid content and proliferation of epithelium and stroma in rat seminal vesicles.

The maintenance of pregnancy in hypophysectomized goats.

Relationship between gonadotrophins, spermatogenesis and seminal plasma.