Maintenance of rate testis fluid testosterone and dihydrotestosterone levels by pregnenolone and other C21 steroids in hypophysectomized rats.

Maintenance of Rete Testis Fluid Testosterone and Dihydrotestosterone Levels by Pregnenolone and Other C2i Steroids in Hypophysectomized Rats1 MARY E. HARRIS AND ANDRZEJ BARTKE Worcester Foundation for Experimental Biology, Shrewsbury, Massachusetts 01545 similar to those seen in the intact rat. Results imply that the maintenance of spermatogenesis by C2i steroids is probably due to the conversion of these compounds to T in the testis. Relatively little T was released from the testis into the peripheral circulation of these rats since T levels in testicular venous plasma were low and peripheral plasma T levels were not distinguishable from those seen in untreated hypophysectomized rats. Histological examination of the testes of C2i steroid-treated hypophysectomized rats showed nearly quantitative maintenance of spermatogenesis and atrophy of Leydig cells. These findings suggest that most of the conversion of C2i steroids to androgens occurred in the seminiferous tubules. (Endocrinology 96: 1396, 1975)

ABSTRACT. This study was undertaken to determine whether maintenance of spermatogenesis in hypophysectomized rats by pregnenolone and other C2i steroids may be due to in vivo conversion of these compounds to androgens. Hypophysectomized rats were treated SC with 2 mg of pregnenolone, 17-hydroxypregnenolone, progesterone, 17-hydroxyprogesterone or testosterone propionate in 0.2 ml sesame oil daily for 14 days beginning 2 days after hypophysectomy. Rete testis fluid (RTF), peripheral blood, and testicular venous blood were collected on the day of the last in ection. Testosterone (T) and dihydrotestosterone (DHT) were measured by radioimmunoassay after chromatographic separation. Results demonstrate that T and DHT could be found in the RTF of C21 steroid-treated hypophysectomized rats at levels

I

T is well known that large doses of testosterone (T) will maintain spexmatogenesis. Moreover, pregnenolone 2 and its esters, compounds practically devoid of androgenic activity, will also maintain spermatogenesis in hypophysectomized rats (1-5). Recently, Steinberger and Chowdhury (6) have studied the effect of pregnenolone and other C2i steroids in hypophysectomized rats. They showed that spermatogenesis was qualitatively maintained but the sex accessories were markedly atrophied. Similarly, Kim and Straw (7) showed that pregnenolone will not maintain seminal vesicle weight in casReceived October 10, 1974. 1 Presented in part at the 6th annual meeting of the Society for the Study of Reproduction, Ottawa, Canada, August, 1974. 2 The following trivial names of steroids are used in the text: pregnenolone, 3/3-hydroxypregn-5-en-20-one; 17-hydroxypregnenolone, 3/3,17a-dihydroxypregn5-en-20-one; 17-hydroxyprogesterone, 17a-hydroxypregn-4-ene-3,20-dione; testosterone propionate, androst-4-ene-17j8-propionate-3-one; dihydrotestosterone, 17/3-hydroxy-5a-androstan-3-one.

trated hypophysectomized rats. These results suggest that if androgens are present in the peripheral circulation of pregnenolone-treated hypophysectomized rats, their concentration is not sufficient to affect the sex accessories. On the other hand, the maintenance of spermatogenesis suggests the possibility that testicular androgen levels may be maintained in these animals. Dihydrotestosterone (DHT) is produced by the testis in several mammalian species (8-14) and seminiferous tubules were shown to convert T to DHT in vitro (8,13,15,16). It has been suggested that in the testis, as in other androgen target tissues, T serves as a pre-hormone and DHT is the physiologically active androgen (15,17). Ahmad and coworkers (18) maintained spermatogenesis in rats with intratesticular implants containing DHT. Chronic treatment with DHT propionate had little effect on restoration of spermatogenesis but was adequate for the maintenance of spermatogenesis (Weisz and Bartke, unpublished). Since rete testis

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RAT RETE TESTIS FLUID AND C,, STEROIDS fluid (RTF) appears to provide a valid estimation of the immediate milieu of the developing germinal epithelium and since T can be measured in rat RTF (19), the present investigation was undertaken to examine the effect of C2i steroids on T and DHT levels in the RTF of hypophysectomized rats.

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to T-Bovine Serum Albumin used crossreacts completely with DHT. The T content of all RTF samples fell within the range of the T assay, and within each group, T and DHT concentration did not vary with the volume of RTF assayed. Histology

The testes were fixed in Zenker-formol solution, embedded in Paraplast and sectioned at 5 (xm. The nuclei of Sertoli cells, type A sperMaterials and Methods matogonia, preleptotene (resting) spermatocytes, pachytene spermatocytes and step 7 Animals spermatids were enumerated in testicular cross Intact and hypophysectomized adult male CD sections stained with hematoxylin and periodic rats, 50 to 59 days old (body weight approxi- acid-Schiff reagent (22) using 12 tubules per mately 175 g for hypophysectomized and over group. The crude counts of nuclei were cor200 g for intact) were obtained from Charles rected by the Abercrombie formula and exRiver Breeding Laboratories. Testosterone pressed per 10 Sertoli cells (22-24). propionate (TP) (Lilly), pregnenolone, 17To examine the morphology of the Leydig hydroxypregnenolone, progesterone and 17- cells, additional groups of intact, hypophysechydroxyprogesterone (Searle) were injected SC tomized-oil-injected and hypophysectomizedin 0.2 ml of sesame oil at a dose of 2 mg per day. pregnenolone injected rats were used (in Hormone treatment was begun 2 or 3 days after collaboration with Dr. M. Dym and Dr. D. W. hypophysectomy. Schedules of treatments are Fawcett). These animals were perfused given in the tables. Rete testis fluid, testicular with 5% glutaraldehyde buffered with 0.2M venous blood, peripheral blood and sex acces- s-collidine. Epon embedded sections (1 /xm sory organs were collected on the day of the last thick) were stained with toluidine blue. hormone injection. Rete testis fluid was collected by a modificaResults tion of the technique of Tuck and colleagues as Treatment of hypophysectomized rats described previously (19). Immediately after RTF collection, blood was collected by cardiac with C2i steroids did not maintain the puncture with a heparinized syringe. Tissues weights of the ventral prostate and the were removed, dissected free of fat, blotted on a seminal vesicles (Table 1). In contrast, paper towel and weighed. While being blotted, weights of caput epididymides in hyposeminal vesicles were emptied of fluid. For physectomized rats treated with pregcollection of testicular venous blood, animals nenolone, 17-hydroxypregnenolone, or 17were anesthetized with Nembutal (Abbot). The testes were exteriorized through a scrotal inci- hydroxyprogesterone were significantly sion, several veins on the surface of the testis increased over hypophysectomized conwere cut with a razor blade and blood was trols. Similarly, testes weights in C2i steroid-treated hypophysectomized rats allowed to drip into a heparinized tube (20). were significantly increased over hypophysectomized controls. Treatment of intact Assay of T and DHT rats with pregnenolone did not produce a Testosterone in fluid and plasma was meas- statistically significant alteration in the ured by radioimmunoassay as described by weights of the sex accessories or of the Bartke and colleagues (21). In this method, DHT, androstenedione, and TP do not interfere testes. Treatment of hypophysectomized rats with T measurement. Dihydrotestosterone was separated from T by chromatography on with pregnenolone maintained the T conSephadex LH-20 columns (21) and measured in centration in the testis fluid at a level the same radioimmunoassay since the antibody which was not significantly different from


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HARRIS AND BARTKE

TABLE 1. Effect of C2i steroids (2 mg/day for 14 days) on organ weights in hypophysectomized rats (mean ± SE) Organ weights (mg) No. of rats

Treatment Intact Intact + pregnenolone Intact + TP Hypox Hypox + pregnenolone Hypox + 17-OH-pregnenolone Hypox + progesterone Hypox + 17-OH-progesterone Hypox + TP

(4)

(5) (5) (8) (8) (5) (3) (6)

(8)

Body weight (g)

367 ± 371 ± 338 ± .164 ±

2 10 7C 8

157 ± 2 L62±6 149 ± 2 151 ± 4 166 ± 4

Ventral prostate

Seminal vesicles

254 ± 23 208 ± 26

283 ± 26 303 ± 18 464 ± 36C

352 ± 33 19 ± 2 35±6 a 17 ± 2 15 ±3 31 ±4 b 281 ± 9d

48 ± 4 45 ± 4 33±2Cb 21 ±2

62 ± 9 482 ± 36d

Caput epididymides

Testis

363 ± 25 379 2t 10 386:t 41 79 dt 4 177:t 8 d 118:t 14b 6 4 :t 4 177:t 14d 278 ± 19d

1,597 ± 95 1,780 ± 31 1,543 ± 150 432 ± 20 971 ± 72d 671 ± 54d 780 ± 54d 761 ± 54d 1,359 ± 50d

P < 0.05; b P < 0.02; c P < 0.01; d P < 0.001 vs control group.

that in the intact animal (Table 2). The three remaining C2i steroids were not as effective as pregnenolone but did increase the T concentration in RTF significantly above the levels observed in hypophysectomized controls. Dihydrotestosterone concentrations in RTF were generally maintained at approximately 10% of T, a situation similar to that seen in the intact controls. Plasma levels of T in these rats were however not distinguishable from the level of T seen in the plasma of oil-treated hypophysectomized control rats. Dihydrotestosterone was nondetectable in the peripheral plasma of hypophysectomized rats treated with C2i steroids. Table 3 shows T concentrations in the RTF, testicular venous plasma and

peripheral plasma in two additional groups

of hypophysectomized rats which were treated with pregnenolone or TP. Note that although the mean T concentration in the testicular venous plasma of intact rats was 148.4 ng/ml, the mean T concentration in the testicular venous plasma of hypophysectomized rats treated with pregnenolone was only 17.5 ng/ml. Histological examination of one testis of each animal used in the present experiments showed that administration of C2i steroids or TP to hypophysectomized rats resulted in maintenance of complete spermatogenesis (Table 4). The mean number of pachytene spermatocytes and spermatids was somewhat lower in hypophysectomized, steroid-treated animals than in

TABLE 2. EflFect of C_2i steroids (2 mg/day for 14 days) on testosterone (T) and dihydrotestosterone (DHT) concentrations in rete testis fluid (RTF) of hypophysectomized rats (mean ± SE) Treatment

Intact Intact + preg Intact + TP Hypox Hypox + preg Hypox + 17 preg Hypox + prog Hypox + 17 prog Hypox + TP

T (ng/ml)

(4) (5) (5) (4) (7) (3) (3) (4) (8)

DHT (ng/ml)

RTF

Plasma

RTF

Plasma

46.5 ± 3.6 37.7 ± 3.4 39.2 ± 4.8 4.9 ± 0.4 35.2 ± 4.8 29.5 ± 3.3a 22.9 ± 1.5" 30.9 ± 1.8 47.2 ±4.1

1.2 dt0.5 1.2 dt0.2 18.5 dt2.9 a 0.5 dt0.08 0.4 dt0.04 0.4 dtO.l

4.9 ± 1.5 2.3 ± 0.8 1.7 ± 0.4a

0.04 ± 0.02 0.02 ± 0.02 0.15 ± 0.07

0.3i t0.05 0.7 ± 0.08 37.3 ± 5.1C

3.3 0.4 2.4 2.0 4.2

± 1.0 ± 0.4a ± 1.0 ± 1.6" ± 0.8

n.d. n.d. n.d. n.d. 3.6 ± 1.9

Preg = pregnenolone; 17 Preg = 17a-hydroxypregnenolone; Prog = progesterone; 17 prog = 17a-hydroxyprogesterone; TP = testosterone propionate; n.d. = nondetectable. Significance of difference vs intact control: a P < 0.05; b P < 0.01; C P < 0.001.


RAT RETE TESTIS FLUID AND C21 STEROIDS

the intact controls, thus resembling earlier observations in rats treated with TP for longer periods (22,23). Representative cross-sections of the testes of intact, hypophysectomized and hypophysectomized pregnenolone-treated rats are shown in Fig. 1. It is evident that 16 days after hypophysectomy both Leydig cells and seminiferous tubules show considerable atrophy and that administration of pregnenolone maintains essentially normal seminiferous tubules without altering the atrophied state of the Leydig cells.

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TABLE 3. Testosterone concentrations in rat rete testis fluid, testicular vein plasma and peripheral plasma (mean ± SE) Testosterone (ng/ml)

Treatment Intact Hypox Hypox + preg* Hypox + TP*

(4) (4) (6) (4)

Testis fluid

Testicular venous plasma

Peripheral plasma

46.5 ± 3.6 4.9 ± 0.4 35.2 ± 4.8 47.2 ±4.1

148.4 ± 11.4 1.0 ± 0.2 17.5 ± 4.8 96.0 ± 8.0

4.1 ± 0.7 0.7 ± 0.1 0.6 ± 0.2 118.0+ 18.4

Preg = pregnenolone; TP = testosterone propionate. • 2 mg steroid/day for 14 days.

absence or low levels of androgen in the peripheral blood. Results of this study Discussion showed that T and DHT concentrations In the hypophysectomized rat, T Pro- were maintained in the RTF of C21 steroidpionate maintains spermatogenesis at doses treated hypophysectomized rats at nearly which are large enough to achieve the normal levels (Table 2). These findings normal concentration of T in the RTF (19). suggest that it might have been the T or Maintenance of spermatogenesis has also DHT, or both, rather than the C21 steroid been demonstrated in hypophysectomized itself which maintained the testis weight rats treated with C2i steroids (6). It there- and spermatogenesis in C2i steroid-treated fore seemed of interest to determine hypophysectomized rats. whether T was present in the RTF of these It appears that relatively little of the T rats, even though their sex accessories present in the RTF of C2i steroid-treated were reported to be atrophied, indicating hypophysectomized rats is released into TABLE 4. Spermatogenesis i n hypophysectomized rats treated with testosterone propionate or C-21 steroids Crude counts (mean ± SE)

Treatment

S

A

Intact controls Hypox controls Hypox + preg Hypox + 17 preg Hypox + prog Hypox + 17 prog Hypox + TP

11.7 ± 0 . 3 25.5 ± 1.4 12.2 ± 0.4 12.5 ± 0.3 11.7 ± 0.5 12.6 ± 0.4 12.3 ± 0.5

1.1 ± 0.3 1.3 ± 0.4 1.2 ± 0.3 1.3 ± 0.4 1.1 ± 0.4 1.3 ± 0.3 1.2 ± 0.3

PL 51.0 ± 48.1 ± 45.8 ± 49.8 ± 49.8 ± 49.6 ± 47.2 ±

1.6 2.1 2.2 1.7 1.7 1.7 1.5

P

SPTDS 7

70.0 ± 2.6 28.0 ± 1.9 62.5 ± 2.8 53.0 ± 2.8 66.3 ± 2.3 64.6 ± 3.8 65.3 ± 1.8

183.1 ± 4 . 1 94.4 ± 9 . 1 157.4 ± 5.9 142.8 ± 7.5 175.6 ± 3.1 146.3 ± 7.1 176.3 ± 3.5

SPTDS 19

True counts corrected by the Sertoli cell factor Intact controls Hypox controls Hypox + preg Hypox + 17 preg Hypox + prog Hypox + 17 prog Hypox + TP •f

\:

0.4 0.2 0.4 0.5 0.4 0.5 0.4

21.9 9.4 18.8 19.9 21.3 19.7 19.3

23.8 4.4 20.3 17.0 22.5 20.3 21.1

73.7 17.4 60.8 53.7 70.7 54.6 67.7

Twelve tubules were counted in each treatment group. Cell counts in all groups were expressed per 10 Sertoli cells. S = Sertoli cells; A = type A spermatogonia; PL = preleptotene spermatocytes; P = pachytene spermatocytes; SPTDS = spermatids; Preg = pregnenolone; 17 Preg = 17-hydroxypregnenolone; Prog = progesterone; 17 prog = 17-hydroxyprogesterone;TP = testosterone propionate. Number of SPTDS 19 in control rats is designated as + + + + +; absence of SPTDS 19 is designated as —.


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HARRIS AND BARTKE

Endo • 1975 Vol 96 • No 6

Leydig cell


RAT RETE TESTIS FLUID AND C21 STEROIDS the peripheral circulation. Levels of T in the testicular venous plasma were very low (Table 3) as were peripheral plasma levels of T and DHT (Tables 2 and 3). In addition, weights of ventral prostates and seminal vesicles were low despite the fact that testis weights were maintained to a significant extent (Table 1). The data on organ weights obtained in the present study are in complete agreement with those of previous workers (1-7). Thus it appears that the C2i steroids are converted to T and DHT within the testis of the hypophysectomized rat. Where in the testis does the conversion of pregnenolone to androgen occur? In hypophysectomized rats treated with pregnenolone or other C2i steroids, T and DHT levels in RTF were high and spermatogenesis was maintained (Table 4) despite atrophied Leydig cells (Fig. 1). The histological evidence for Leydig cell atrophy is in complete agreement with Tache et al. (25). Decreased activity of the Leydig cells was also indicated by the low levels of T in the testicular venous plasma. These data, and particularly the simultaneous occurrence of normal T levels in RTF and drastically reduced T levels in testicular venous blood, suggest that in the hypophysectomized C2i steroid-treated rat, unlike in the normal animal, most of the T does not originate in the Leydig cell. Possibly cells within or in close proximity to the tubules were responsible for the in vivo conversion of C2i steroids to T. The idea of C21 steroids entering the tubule and being converted by the tubule

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to testosterone is strongly supported by the work of others in this area. In rats and rabbits, both pregnenolone and progesterone readily enter the seminiferous tubules after being administered systemically or via the spermatic artery (26-28). Non-flagellate germ cells from rat testis will bind progesterone as well as T and DHT (29). The isolated seminiferous tubules in vitro can convert progesterone or pregnenolone to T (30-32). Finally, Haltmeyer and Eik-Nes (33) have indicated a possibility that DHT present in the spermatic lymph of the dog may be produced outside the Leydig cells. Thus the results of the present chronic in vivo experiments support the results of the acute in vivo and in vitro experiments of previous workers. An interesting observation was made in examining tissue weights in the animals used in the present experiments (Table 1). The weights of the caput epididymides in three of the four groups of C2i steroidtreated hypophysectomized rats were maintained at approximately Vz to V3 of that seen in the intact controls. In contrast, ventral prostate and seminal vesicles weights were very poorly maintained by C2i steroid treatment. This may indicate that caput epididymal weight depends more on the testicular than on the peripheral androgen level. This finding was not unexpected since testis fluid rich in T flows into the epididymis where it is absorbed in the caput. Along these lines Dinakar et al. (34) have shown that the epididymis of the castrated rhesus monkey

FIG. 1. Top left: Leydig cells of an intact adult rat; N = nucleus; * = cytoplasm. Top right: Leydig cells of a rat hypophysectomized for 16 days and treated with sesame oil. Note reduction in Leydig cell volume and scarcity of cytoplasm. D = degenerating germ cell. Bottom left: Leydig cells of a rat hypophysectomized for 16 days and treated with 2 mg of pregnenolone per day beginning 2 days after hypophysectomy. Note reduction in Leydig cell volume and scarcity of cytoplasm similar to that seen in the hypophysectomized oil-injected rat. Bottom right: Seminiferous tubules of hypophysectomized-pregnenolone-treated rat (as in bottom left). Note complete spermatogenesis. Sections prepared and photographed by Dr. M. Dym and Dr. D. W. Fawcett of Harvard Medical School. Toluidine blue stain. Magnification of Leydig cells: approximately x980; seminiferous tubules, approximately x300. Details in the text.


HARRIS AND BARTKE

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has a higher threshold requirement for exogenously administered androgen than do the other accessory glands. The maintenance of epididymal weight with C2i steroids observed in the present study was probably also due, in part, to the maintenance of sperm production and the resulting content of spermatozoa in the epididymal duct. In conclusion, this report has shown that the maintenance of spermatogenesis in hypophysectomized rats treated with pregnenolone or other C2i steroids can be explained by the normal levels of T and DHT present in the rete testis fluid of these animals. The present results together

with the earlier observations of others suggest that seminiferous tubules may have been responsible for most of the observed conversion of C2i steroids to androgens. It is not known whether this apparent capacity of seminiferous tubules to produce considerable amounts of androgens is ever realized in intact animals. However, it seems possible that seminiferous tubules usually convert nonandrogenic steroids, derived either from the Leydig cells or from extratesticular sources, into T .and DHT and thus contribute to the high concentrations of these androgens in the immediate vicinity of the dividing and differentiating germinal cells. Acknowledgments This work was supported by Steroid Training Program NIH 5 TO 1AM-05564-17, by the Elijah Romanoff Assistance Program and by PHS Fellowship 1 F22 HD01219 (MEH), by NICHD Research Career Development Award 5 KO4 HD70369 and by NICHD grant 1 R01 HD06867 (AB). We thank Ms. Susan Dalterio for her excellent technical assistance, Dr. B. V. Caldwell for the testosterone antiserum and Dr. L. Ewing for helpful suggestions.

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6. Steinberger, E., and A. K. Chowdhury, Endocrinology 92: Suppl, A-97, 1973. 7. Kim, K. S., and J. A. Straw, Physiologist 14:-171, 1971. 8. Sowell, J. G., Y. Folman, and K. B. Eik-Nes, Endocrinology 94: 346, 1974. 9. Rose, L. I., R. H. Underwood, D. E. Parker, and G. H. Williams,/ Clin Endocrinol Metab 36: 995, 1973. 10. Haltmeyer, G. C., and K. B. Eik-Nes, J Reprod Fertil 36: 41, 1974. 11. Ganjam, V. K., and R. P. Amann, Ada Endocrinol (Kbh) 74: 186, 1973. 12. Pazzagli, M., D. Borrelli, G. Forti, and M. Serio, Ada Endocrinol (Kbh) 76: 388, 1974. 13. Folman, Y., J. G. Sowell, and K. B. Eik-Nes, Endocrinology 91: 702, 1972. 14. Tremblay, R. R., M. G. Forest, J. Shalf, J. G. Martel, A. Kowarski, and C. J. Migeon, Endocrinology 91: 556, 1972. 15. Payne, A., A. Kawano, and R. B. Jaffee, J Clin Endocrinol Metab 37: 448, 1973. 16. Rivarola, M. A., and E. J. Podesta, Endocrinology 90: 618, 1972. 17. Steinberger, E., Physiol Rev 51: 1, 1971. 18. Ahmad, N., G. C. Haltmeyer, and K. B. Eik-Nes, Biol Reprod 8: 411, 1973. 19. Harris, M. E., and A. Bartke, Endocrinology 95: 701, 1974. 20. de Jong, F. H., A. H. Hey, and H. J. van der Molen, J Endocrinol 57: 277, 1973. 21. Bartke, A., R. E. Steele, N. Musto, and B. V. Caldwell, Endocrinology 92: 1223, 1973. 22. Clermont, Y., and H. Morgentaler, Endocrinology 57: 369, 1955. 23. , and S. C. Harvey, Ciba Fdn Colloq Endocrinol 16: 173, 1967. 24. Bartke, A., and C. W. Lloyd,/ Endocrinol 46: 321, 1970. 25. Tache, Y., H. Selye, S. Szabo and J. Tache, J Endocrinol 58: 233, 1973. 26. Parvinen, M., P. Hurme, and M. Niemi, Endocrinology 87: 1082, 1970. 27. Galjaard, H., J. H. von Gaasbeek, H. W. A. De Bruyn, and H. J. van der Molen, 7 Endocrinol 48: li, 1970 (Abstract). 28. Cooper, T. G., and G. M. H. Waites, / Reprod Fertil 31: 506, 1972. 29. Galena, H. J., and C. Terner, J Endocrinol 60: 269, 1974. 30. Bell, J. B. G., G. P. Vinson, and D. Lacy, Proc R Soc Lond B 176: 433, 1971. 31. Hall, P. F., D. C. Irby, and D. M. de Kretser, Endocrinology 84: 488, 1969. 32. Christensen, A. K., and N. R. Mason, Endocrinology 76: 646, 1965. 33. Haltmeyer, G. C , and K. B. Eik-Nes, J Reprod Fertil 36: 41, 1974. 34. Dinakar, N., R. Arora, and M. R. N. Prasad, J Endocrinol 60: 399, 1974.


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

Effects of C21 steroids on sex accessory organs and testes of mature hypophysectomized rats.

Regulation of testosterone and dihydrotestosterone levels in rete testis fluid. Evidence for androgen biosynthesis in seminiferous tubules in vivo.

Testosterone and dihydrotestosterone concentrations in plasma, epididymal tissues, and seminal fluid of adult rats.

Age-related secretion of androstenedione, testosterone and dihydrotestosterone by the human testis.

Serum pregnenolone, progesterone, 17alpha-hydroxyprogesterone, androstenedione, testosterone, 5alpha-dihydrotestosterone and androsterone during puberty in boys.

Binding interactions of progesterone and other C21 steroids with rat uterine cytosol.

The effect of estrogens on luteinizing hormone plasma levels and on testosterone production in intact and hypophysectomized rats.

Maintenance of serum somatomedin activity in hypophysectomized pregnant rats.

Temporal changes in the serum levels of gonadotrophins and testosterone in male rats bearing subcutaneous implants of 5 alpha-dihydrotestosterone.

Simultaneous solubilization of steroid hormones I: estrogens and C21 steroids.

Effects of relaxin in combination with prolactin and ovarian steroids on mammary growth in hypophysectomized rats.

Testosterone and 5alpha-dihydrotestosterone inhibit both growth and spermatogenesis in the remaining testis in partially castrated adult newts, Notophthalmus viridescens.

Seminal plasma levels of testosterone and 5 alpha-dihydrotestosterone in azoospermic patients.

Alterations in brain atrial natriuretic polypeptide levels in hypophysectomized rats.

Chronic stress increases estrogen and other steroids in inseminated rats.

Transformation of C18-, C19- and C21-steroids by cultures of Candida albicans.

The maintenance of pregnancy in hypophysectomized goats.

Splanchnic extraction and conversion of testosterone and dihydrotestosterone in man.

Plasma testosterone and dihydrotestosterone in ovulatory and anovulatory cycles.

Action of testosterone, dihydrotestosterone and 5alpha androstane 3alpha, 17beta diol on the spermatogenesis of immature rats.

Formation of 5alpha-reduced C19-steroids from progesterone in vitro by a pathway through 5alpha-reduced C21-steroids in ovaries of late prepubertal rats.

Synergistic effects of follicle-stimulating hormone and testosterone on the maintenance of spermiogenesis in hypophysectomized rats: relationship with the androgen-binding protein status.

Role of testosterone and dihydrotestosterone in spontaneous gynecomastia of adolescents.