Influence of adrenalectomy on maturation of gonadotrophin function in the male rat.

The effects were studied of adrenalectomy performed at 25 days of age on the maturation of LH function and the testes during puberty (i.e. 30-50 days of age) in the male rat. In intact rats the plasma LH level increased and then decreased and the plasma testosterone level increased progressively. In adrenalectomized rats the plasma levels of LH and testosterone did not vary significantly over the same period of time. Adrenalectomy decreased the plasma levels of LH and testosterone. The different perturbations in hormonal balance induced a decrease in the size of the seminiferous tubules and a delay in spermatogenesis.

The adult dogfish (Scyliorhinus canicula L.) testis: a model to study stage-dependent changes in steroid levels during spermatogenesis.

The unit structure of the testis of Scyliorhinus canicula L. is the seminiferous lobule arranged in topographically distinct zones and comprised of cysts formed by steroid-producing Sertoli cells associated with germ cells at an identical stage of spermatogenesis. In this experiment, testicular tissues from different dogfish corresponding to the zones of lobules with spermatogonia (A), spermatocytes (B), early spermatids (C) and late spermatids (D) were dissected out and pooled. They were either used for steroid radioimmunoassay or incubated to measure steroid production in response to dogfish pituitary extract or to dibutyryl cyclic AMP (dbcAMP). Our results indicate that testosterone is the main testicular androgen in this species. Furthermore, marked changes in the distribution of steroids were observed according to the zone of spermatogenesis, testosterone concentrations being highest in zones A and D. The relative contents of this hormone (steroid levels normalized to an equivalent number of Sertoli cells) as well as of delta 4-androstenedione and of progesterone increased from A to D. The concentrations of delta 4-androstenedione and progesterone were highest in zone D. Relative contents of 5 alpha-androstane-3 alpha,17 beta-diol, dihydrotestosterone and 11-ketotestosterone were very low in A when compared with the other zones. Finally, whereas no significant stage-related variation in the concentration of oestradiol-17 beta and 17 alpha-hydroxy, 20 beta-dihydroprogesterone was observed, the relative content of these steroids was lowest in zone A. Incubation experiments revealed that dogfish pituitary extract and dbcAMP can stimulate androgen synthesis (about twofold) and that a stage-related change of steroid responsiveness to dbcAMP exists (only zones A and D were responsive). Overall, the results of this study indicate that germ cells most probably influence Sertoli cell steroidogenesis and responsiveness in the adult dog fish testis.

Studies of the androgen binding protein in the rete testis fluid of the ram and its relation to sexual season.

An androgen binding protein (ABP) with an electrophoretic mobility (Rf) of 0.56 is present in the rete testis fluid of adult rams. Its steroid specificity was found to be in the following order: 5alpha-DHT, testosterone, oestradiol-17 beta, dehydroepiandrosterone 5beta-DHT, androstenedione, cyproterone, cyproterone acetate, cortisol and progesterone. The characteristics of the ABP are similar to those found for the ABP of the testis and the epididymis of the rat and the rabbit. The concentration of ABP, determined by the dextran-coated charcoal method and sometimes confirmed by the steady-state polyacrylamide gel electrophoresis method, was significantly higher in the breeding season than in the non-breeding season (4.40 +/- 0.98 X 10(-9) M vs. 2.60 +/- 0.62 X 10(-9) M; P less than 0.037). The affinity constant of the ABP was independent of the season (2.45 +/- 0.21 X 10(9) M-1 vs. 2.66 +/- 0.1 X 10(9) M-1; NS). In addition, ABP was positively correlated with 5alpha-DHT (r = 0.506; P less than 0.0009), testosterone (r = 0.445; P less than 0.0003), total protein (r = 0.329; P less than 0.02) and spermatozoa (r = 0.406; P less than 0.006) in the RTF and with blood plasma testosterone (r = 0.584; P less than 0.0001). Furthermore, testosterone and 5alpha-DHT in RTF were positively correlated (r = 0.582; P less than 0.0001). These androgens were also correlated with plasma testosterone (r = 0.262, P less than 0.052 for testosterone in RTF; r = 0.341, P less than 0.018 for 5 alpha-DHT). Total proteins and spermatozoa were found to be positively correlated in the RTF (r = 0.789; P less than 0.0001).

Influence of germ cells upon Sertoli cells during continuous low-dose rate gamma-irradiation of adult rats.

The effects of continuous gamma-irradiation of adult rats at two low-dose rates (7 cGy and 12 cGy/day; up to a total dose of 9.1 Gy and 10.69 Gy 60Co gamma-ray, respectively) were investigated. Over a period of 3-131 days of irradiation, groups of experimental and control animals were killed. Body weight, testis, epididymis, prostate and seminal vesicle weights, the number of germ cells and Sertoli cells, tubular ultrastructure, epididymal and testicular levels of biologically active androgen-binding protein (ABP), and the plasma concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone were monitored. Irradiation had no effect on body weight, whereas testicular and epididymal weight began to decrease following 35 and 50 days of irradiation at 7 and 12 cGy, respectively. At 7 cGy the target cells of the gamma-rays were essentially A spermatogonia, whereas at 12 cGy A spermatogonia and preleptotene spermatocytes were primarily affected. This resulted in a progressive and sequential dose-related reduction in the number of pachytene spermatocytes, round spermatids and late spermatids (LS). Under both irradiation procedures the Sertoli cell number remained unchanged whereas partial (7 cGy) or no change (12 cGy) was seen at the Leydig cell level. Whatever the irradiation protocol, from the time LS numbers decreased, vacuolisation of the Sertoli cell cytoplasm progressively occurred, followed by thickening and folding of the peritubular tissue. Moreover, in parallel to the drop in the number of these germ cell types, ABP production fell whereas FSH levels rose. A highly significant positive correlation was found between LS numbers and these Sertoli cell parameters. This study supports our previous concept of a control of certain important aspects of Sertoli cell function by late spermatids in the adult rat.

Induction of maternal behavior in incubating and non-incubating hens: influence of hormones.

Maternal responses and variations in plasma levels of prolactin and testosterone have been studied in incubating and in non-incubating, non-laying hens during forced adoption experiments. The results demonstrate the ability of incubating hens to display complete maternal behavior as early as the 10th day of incubation after being exposed to stimulation by chicks during one night. Maternal responses also emerged in non-laying hens but more gradually. In both groups, a decline in plasma testosterone occurred after the introduction of the chicks and, in the incubating hens, prolactin levels fell as they abandoned their nests.

Androgen and estrogen levels in the plasma of Pleurodeles waltl, Michah., during the annual cycle. I. Male cycle.

Sex steroid levels in the plasma of the male Pleurodeles waltl were determined by radioimmunoassay of blood samples taken monthly from each newt during an 18-month period. Androgen levels varied according to season with annual peaks in October-November and in March. The position of these two peaks was the same in the 2 years studied. Testosterone was the principal androgen measured, while the levels of dihydrotestosterone and 4-androstenedione were lower but fluctuated in parallel with that of testosterone. The 17 beta-estradiol levels were very low or undetectable. Androgen levels during the year were synchronous between the several newts studied. The cyclical variations in the steroid levels agreed with the morphological modifications of sexual characteristics during the annual cycle.

Androgen and estrogen levels in the plasma of Pleurodeles waltl, Michah., during the annual cycle. II. Female cycle.

Sex steroid levels in the plasma of the female Pleurodeles waltl were determined by radioimmunoassay of blood samples taken monthly from each newt during an 18-month period. Estradiol-17 beta levels were relatively high (greater than 1 ng/ml) but androgen levels were higher (2-30 ng/ml). Androgen and estradiol-17 beta levels fluctuated according to season with two annual peaks, in autumn and in March. Testosterone was the principal androgen present in this plasma. Dihydrotestosterone levels were relatively low but showed slight fluctuations during the year. 4-Androstenedione and estrone levels were very low and relatively constant throughout the seasons. Fluctuations of androgen and estradiol-17 beta levels were synchronous between the several newts studied during the year. The ratio [E2-17 beta]/[Androgen] was stable during the major part of the year (0.2-0.3) except in July and August, when it reached the value of 1.0. The seasonal variations in the steroid levels were well correlated to the morphological modifications of sexual characteristics during the year.

Stage-dependent modulation of Sertoli cell steroid production in dogfish (Scyliorhinus canicula).

Seminiferous lobules of dogfish (Scyliorhinus canicula) testis comprise cysts formed by steroid-producing Sertoli cells associated with germ cells at an identical stage of spermatogenesis. These lobules were isolated in four populations corresponding to lobules with spermatogonia (A), spermatocytes (B), early spermatids (C) and late spermatids (D). They were used for steroid radioimmunoassay or incubated with 22 alpha-hydroxycholesterol or with dibutyryl cyclic AMP (dibutyryl cAMP) to measure steroid production. Our results indicate that progesterone was the major steroid in seminiferous lobules at all stages of spermatogenesis except in lobules A. Furthermore, marked changes in the distribution of steroids were observed according to the stage of spermatogenesis; progesterone, 4-androstenedione, testosterone and 17 alpha-hydroxy,20 beta-dihydroprogesterone concentrations were highest in lobules D, whereas dihydrotestosterone concentrations decreased during spermatogenesis. No significant stage-related change was observed for 3 alpha-diol and 3 beta-diol. Incubation experiments revealed that the isolated seminiferous lobules at all stages can synthesize steroids from hydroxycholesterol and that lobules D have the highest basal contents of androstenedione and testosterone. Furthermore, when dibutyryl cAMP and 10 mumol hydroxycholesterol l-1 were added together to the cultures, an enhancement of the steroid secretion was observed rather than a change in synthesis. Our results also indicated that the responsiveness of the lobules to dibutyryl cAMP varies according to the stage of spermatogenesis and to the steroid assayed. Overall, this study indicated that germ cells probably markedly influence Sertoli cell steroidogenesis in the adult dogfish testis.

Sexual steroids in Salamandra salamandra (L.) during ontogeny.

In order to investigate the ontogeny of steroid secretions during the juvenile phase, sexual steroids were extracted and assayed after chromatographic separation in the gonads and plasma of male and female salamanders Salamandra salamandra L. at three characteristic postlarval stages. All specimens were collected in the wild. The immature stage is characterized, in the female, by high dihydrotestosterone (DHT) and 5 alpha-androstandiol levels, low progesterone concentration, and an absence of testosterone in the ovary. Just before sexual maturity a regular increase in plasma levels of estradiol and testosterone was observed. In the male, progesterone and DHT are at a relatively high level in the testis of the immature stage but concentrations decrease in subadults. In young adults, concentrations of progesterone are greater than they are in the immature animals. Sexual maturity is characterized by a large increase in testicular and plasma testosterone as well as a relative decrease in DHT, 5 alpha-diols, and estrone. The progesterone liberated into the plasma was negligible. Diols seem to play an important part in the ontogeny of sexual function.

[Plasma estrogens in Pleurodeles waltlii. Comparison between diploid and triploid females].

Estrogens have been examined in the plasma of diploid and triploid newts Pleurodeles waltlii. Estradiol-17 beta (E2) and estrone (E1) were determined by radioimmunoassay, before and after enzymatic hydrolysis of the conjugates. Total (t) and unconjugated (u) E2 levels were positively correlated (E2u = 0.478 35 E2t + 0.579 98; r = 0.883), but no correlation was detected between E1 levels. No statistical difference was found for the estrogen levels between the different experimental lots of diploid newts (E2t = 7.5 +/- 0.37 ng/ml, E2u = 4.3 +/- 0.20 ng/ml, E1t = 2.19 +/- 0.08 ng/ml, E1t = 0.41 +/- 0.02 ng/ml) but every estrogen level was lower in the triploid group (E2t = 1.8 +/- 0.60, E2u = 1.0 +/- 0.18, E1t = 1.4 +/- 0.13, E1u = 0.3 +/- 0.04 ng/ml). This difference is discussed in relation to lower fertility of the triploid females.

Changes in plasma gonadotrophins after neurotropic stress in the postnatal castrated male rat. Influence of adrenalectomy.

In 60-day-old postnatal castrated male rat, neurotropic stress increased plasma levels of LH, FSH, ACTH, corticosterone, testosterone and 17 beta-oestradiol. The possible influence of ACTH in the observed increase in plasma sex steroids was discussed. After adrenalectomy, performed at 50 days of age, neurotropic stress no longer affected plasma gonadotrophin level significantly. Adrenalectomy, raising plasma level of corticotrophin and decreasing plasma levels of testosterone and 17 beta-oestradiol, created conditions favorable to inhibition of gonadotrophin function.

Seasonal variations in sex steroids and male sexual characteristics in Scyliorhinus canicula.

Concentrations of testosterone, progesterone, Delta4-androstenedione, dihydrotestosterone, 11-ketotestosterone, estrone, estradiol-17beta, 5alpha-androstane, 3alpha, 17beta-diol, and 17alpha-hydroxy, 20beta-dihydroprogesterone were determined by radioimmunoassays in the blood plasma and testicular homogenates of Scyliorhinus canicula. Samples were collected almost every month for 27 months. The weights and sizes of reproductive organs and sperm reserves were also measured over the same period. Quantitatively, testosterone was the principal steroid present. Testicular and epididymal weights, sperm reserves, and clasper size varied throughout the year, but not always in a synchronous fashion. Most of the testicular steroids had an annual peak, generally in February, except for progesterone. The plasma concentrations of progesterone, Delta4-androstenedione, and androgens presented various degrees of fluctuation over the year, but were not synchronized: maxima occurred during autumn-winter for androgens and progesterone, during spring for Delta4-androstenedione. Thus, various aspects of S. canicula reproductive function appear to be influenced by season, the sea temperature being, most probably, a major determinant in this respect.

Induction of maternal behavior and some hormonal and physiological correlates in the domestic hen.

The manifestation of maternal behavior and the variations of plasmatic levels of gonadic hormones (testosterone, delta 4-androstenedione, and 17 beta-estradiol) have been studied in two groups of domestic hens (layers and nonlayers) during a forced adoption experiment. Maternal behavior appears later in actively laying hens than in nonlayers. The former hens show a higher level of androgens (T and delta 4). The appearance of typical maternal behavior coincides with a pause in laying and a decrease in all the plasmatic steroid levels measured.

[Male sexual behavior induced by testosterone in ovariectomized adult ewes. Effect of the dose and previous sexual experience]. / Etude du comportement sexuel mâle induit par la testostérone chez des brebis adultes ovariectomisées. Effet de la dose et de l'expérience sexuelle antérieure.

Adult ovariectomized ewes, daily injected with testosterone propionate (2 to 22 mg), showed male-like sexual behaviour, never seen in untreated females, but very similar to that in normal rams. After a few days of latency (3 days minimum), this behaviour gradually appeared and increased in frequency until a plateau was reached. The time-course in which the plateau was reached depended on the androgen dose and on previous experience with male sexual behaviour. Some male-like behaviour might have persisted after the end of the treatment. The results have been discussed in terms of possible mechanisms of action on the central nervous system.

Comparative plasma levels of androgens and 17 beta-estradiol in the diploid and triploid newt, Pleurodeles waltl.

Seasonal changes in the plasma levels of androgens (testosterone plus dihydrotestosterone) and 17 beta-estradiol in diploid and triploid adult newts, Pleurodeles waltl were studied. In both male and female diploid individuals, large variations were reported with highest levels being found during breeding periods. In triploid newts seasonal variations were also found, similar to the diploid ones, but the plasma concentrations of the 17 beta-estradiol and androgens in triploid females and androgens in triploid males were lower throughout the year than those reported for the diploids. This difference is discussed in relation to the genetic sexual constitution.

Seasonal variations of androgens, estrogens, and progesterone in the different lobules of the testis and in the plasma of Salamandra salamandra.

Progesterone, 4-androstenedione, testosterone, dihydrotestosterone, 5 alpha-androstane-3 alpha,17 beta-diol (3 alpha-diol), 5 alpha-androstane-3 beta, 17 beta-diol (3 beta-diol), estrone, and estradiol levels were determined by radioimmunoassay in the different lobules of the testis of Salamandra salamandra throughout the year according to the seasonal cycle. 3 beta-diol levels were not detectable. High levels of steroids were found in the grandular tissue (enlarged pericystic cells after spermiation) and large variations were showed for progesterone, 4-androstenedione, testosterone, 3 alpha-diol, and estrone. In the mature lobule (formed by cysts with mature spermatozoa), only testosterone showed seasonal variations and in the immature lobule (with early stages of meiosis), 3 alpha-diol showed fluctuations. The major estrogen found in the testis of Salamandra was estrone; estradiol stayed at a low level throughout the cycle. The steroids fluctuation seems to be related to the histological evolution of the testis throughout the cycle. The present data were the first on steroid seasonal variations in the testis of an urodele.

Plasma concentration of LH and testosterone in castrated rams treated with testosterone or testosterone propionate.

After injection of castrated rams with 600 mg testosterone or testosterone propionate, plasma LH levels were biphasic, with significant decreases at 6-10 and 96 h after treatment. These results support the suggestion that testosterone acts at the hypothalamo-pituitary level by two different mechanisms.

PIP: Plasma concentrations of luteinizing hormone (LH) and testosterone were measured in 14 castrated rams treated with 600 mg of testosterone or testosterone propionate. Plasma LH levels were biphasic with significant decreases at 6-10 and 96 hours after treatment (p less than .001). The magnitude of the testosterone fluctuations indicates that resorption rate and/or metabolism are highly variable. Although testosterone levels increased more rapidly after testosterone than after testosterone propionate, testosterone appeared to inhibit the release of LH for a longer period. These results support the suggestion that testosterone acts at the hypothalamo-pituitary level by 2 different mechanisms.

Regional distribution of steroids in the dog epididymis.

Concentrations of delta 4 androstenedione, testosterone and dihydrotestosterone were measured in the post-nuclear supernatant of the dog epididymis. In addition, they were measured in the efferent ducts and the testis. From the efferent ducts to the corpus there was a significant decrease in testosterone and delta 4 androstenedione concentrations. On the contrary, the concentration of dihydrotestosterone increased from the efferent ducts to the corpus where this steroid predominated. The marked differences in steroid concentration along the epididymis of the dog suggested regional differences in androgen metabolism.

[Evidence for testosterone induced prealbumin secretion in ram epididymis]. / Misc en évidence chez le bélier d'une préalbumine sécrétée par l'épididyme sous l'action de la testostérone.

The fluids of the Rete Testis and of the different areas of the epididymis (caput, corpus, cauda) were collected by micropuncture of the Rete Testis or the epididymal duct from caput and corpus of normal Rams (n = 3) and 4 months orchidectomized Rams having in the last month a subcutaneous implant testosterone (200 mg) which delivered a constant rate of testosterone for 4 weeks. Homogenates of epididymal tissues from orchidectomized Rams (3 months) were prepared in saline (n = 4). All samples diluted in saline, were centrifuged and submitted to polyacrylamide slab gel electrophoresis (7.5% acrylamide) at pH 8.3. Results showed an alpha-globulin Rf 1.1 whose molecular weight was approximately 105,000 D which was clearly detected into the fluid of the caput or corpus epididymis, weakly in the cauda epididymis of normal Rams and at the 3 levels of the epididymis of the testosterone supplemented castrates; it was absent in tissues of castrated Rams not supplemented with testosterone supplemented castrates; it was absent in tissues of castrated Rams not supplemented with testosterone. Results were discussed according to epididymal sperm maturation.