Testicular Steroidogenic Activity Research Articles

Melatonin intake since weaning ameliorates steroidogenic function and sperm motility of streptozotocin-induced diabetic rats.

Melatonin may be used as an antioxidant in therapy against systemic sequelae caused by oxidative stress in diabetes. However, as melatonin has a major role in regulating reproductive activity, its consequence on reproductive parameters under diabetes needs to be better clarified. We have studied whether prior and concomitant treatment of juvenile Wistar rats with low doses of melatonin interferes in reproductive damage induced by experimental diabetes after 1 and 8weeks. The consequences of melatonin administration since weaning on reproductive parameters of healthy rats at adulthood were also evaluated. Melatonin was provided in drinking water (10μg/kg b.w./day) after weaning (5-week-old). Diabetes was induced by streptozotocin injection (4.5mg/100g b.w.) at 13-week-old rats, and rats were euthanized 1 and 8weeks after disease onset. Diabetes decreased circulating testosterone levels (~35% to 1week; ~62% to 2months; p<0.01) but did not affect testes sperm counts. Twomonths of diabetes reduced the sperm reserve and led to atrophy of epididymal cauda. Both 1-week and 2-month diabetes impaired sperm motility, decreased the number of spermatozoa with progressive movement, and increased the number of immotile sperm. Melatonin intake reduced serum testosterone levels ~29% in healthy 14-week-old and ~23% in 21-week-old rats and reduced daily testicular sperm production ~26% in the latter disease stage, but did not interfere in sperm reserves and transit time for both experimental periods. Exogenous melatonin prevented the serum testosterone decrease and damage to sperm motility in diabetic rats and attenuated reduction in sperm counts and transit time induced by 1-week diabetes but did not avoid this decrease at 2-month diabetes. Low doses of melatonin administered prior to and during experimental diabetes attenuated damage to testicular steroidogenic activity and preserved sperm motility, but not sperm reserves in the rat. Our data indicated a differential action of melatonin in normoglycemic and hyperglycemic conditions, particularly in sperm motility and testosterone production by Leydig cells.

Interrelationship between NO and androgenic activity in mice, Mus musculus, following temporal phase relation of serotonergic and dopaminergic neural oscillations

The present study was designed to monitor the correlation of gonadal steroidogenic activity and nitric oxide (NO) of plasma and testis of male laboratory mouse, Mus musculus, under (1) control/basal and (2) experimental conditions. In the first study, male mice (n = 6) of three age groups (3-week-old sexually immature, 9-week-old sexually mature and 1.5-year-old) were assayed for plasma testosterone and level of NO in the plasma and testis. The immunoreactivity of 3-β-hydroxysteroid dehydrogenase (3-β-HSD) and androgen receptors (ARs) was also detected in testis and epididymis, respectively. In the second study, the reproductive state of mice was altered by injecting precursors of serotonin 5-hydroxytryptophan (5-HTP) and dopamine L-dihydroxyphenylalanine (L-DOPA) daily for 13 days. In one subgroup, mice received their daily injections 8 h apart and in another subgroup 12 h apart. A third subgroup of control mice received two daily injections of normal saline. After the completion of the experiment, the mentioned parameters were measured. The results showed a significant increase in levels of NO and a lowering of the immune reactivity of 3-β-HSD and AR, in both leydig cells and the epididymis in the sexually immature, old-age mice as well as in the mice that received 5-HTP and L-DOPA in the 8-h temporal relation, whereas opposite effects were observed in the sexually mature mice as well as in the mice that received 5-HTP and L-DOPA in the 12-h temporal relation. These findings led us to conclude that an inverse correlation exists between testicular steroidogenic activity and NO activity of laboratory mice under control and experimentally modulated gonadal conditions.

Temperature dependent action of growth hormone on somatic growth and testicular activities of the catfish, Clarias batrachus

Effects of growth hormone on somatic growth and testicular activities were studied during late quiescence and early recrudescence phases of the reproductive cycle of the catfish, Clarias batrachus. The administration of exogenous growth hormone (GH) during the late quiescence phase (December–January; ambient water temperature-15.2±1°C) did not influence the somatic growth as well as the testicular activity, as no change in body weight, testis weight, plasma level of insulin-like growth factor I (IGF-I) and testicular morphology was detected following GH treatment, though the plasma testosterone was marginally increased. While during the early recrudescence phase (March–April; ambient water temperature-28.1±2°C), GH treatment promoted the production of insulin like growth factor-I and testicular steroidogenic activity in a dose dependent manner, as was evident from the significant increase in the circulating levels of testosterone and estradiol-17β. GH treatment also increased body weight, testicular weight and gonadosomatic index, suggesting its involvement in testicular development. The GH treatment promoted spermatogonial proliferation and accelerated the spermatogenic process in the present catfish. These results, thus, suggest that GH influences the somatic growth and testicular activities depending on the temperature of the rearing water; warmer temperature and longer photoperiod promote testicular steroidogenic and spermatogenic activities in fish. This study has immense practical use in fisheries science.

Impairment of Spermatogenesis in Rats by Mercuric Chloride: Involvement of Low 17β-Estradiol Level in Induction of Acute Oxidative Stress

Mercuric chloride (HgCl(2)) has been shown to affect the male reproductive organs, and oxidative stress has been linked with hypospermatogenesis and with male infertility. However, the specific mode of impairment of spermatogenesis during HgCl(2) exposure has not yet been clarified fully. Because of the involvement of 17β-estradiol (E2) in the male reproductive tract and its putative role on spermatogenesis, the present study aimed to investigate the possibility that HgCl(2)-induced oxidative stress-mediated modulation of the E2 level exerts adverse effects on testicular steroidogenic and gametogenic activities. HgCl(2) treatment at 50 and 100ppm for 90days by continuous oral administration in the drink water resulted in significant dose-dependent fashion decrease in serum and testicular E(2) levels and an increase in testicular testosterone levels in dose-dependent manner, without statistical alteration in serum testosterone level among HgCl(2) exposed groups compared to the control. Cauda epididymal sperm count and motility were decreased significantly (p < 0.01), in a dose-dependent manner, in the HgCl(2)-treated groups, and qualitative examination revealed inhibition of spermatogenesis and the preferential loss of maturing and elongated spermatids. The seminiferous tubules were dilated in treated animals. When compared to the control, increase in lipid peroxidation due to toxic effects of HgCl2 was accompanied by significant reduction (p < 0.01) in antioxidant enzymes activities, superoxide dismutase, catalase, and glutathione peroxidase of testes, implicating the presence of oxidative tissue damage. Furthermore, these tissue injuries caused functional impairment as evidenced with testicular elevated activity of lactate dehydrogenase. Unless oxidative stress can lead to cancer development, testis' tumor markers as beta human chorionic gonadotropin and alpha-fetoprotein levels have shown no significant differences in the HgCl(2)-exposed group compared with respect to the control. Large quantities of metal accumulated in the testis tissue are in agreement with the testis-activity failure verified in this tissue. These findings suggest that a decrease in E2 level after mercury exposure may render testis more susceptible to oxidative damage leading to its functional inactivation, thus providing new dimension to mechanisms underlying heavy metal-induced male infertility.

Possible role of pituitary in Mitomycin C induced inhibition of testicular steroidogenesis.

To find out the role of pituitary in Mitomycin C (MC) induced reduction of testicular steroidogenesis, MC was administered along with HCG and the testicular steroidogenic activity was assessed on the basis of different parameters which are directly and indirectly related to the rate of testicular steroid biogenesis. The results indicate that MC induced reduction in testicular steroidogenesis is not only due to its direct effect but suppression of pituitary gonadotrophin secretion may be one of the responsible factor.

Seasonal changes in fecal testosterone concentrations and their relationship to the reproductive behavior, antler cycle and grouping patterns in free-ranging male Pampas deer ( Ozotoceros bezoarticus bezoarticus)

The purpose of this study was to validate noninvasive endocrine monitoring techniques for Pampas deer and to evaluate seasonal changes in testicular steroidogenic activity and their correlation to reproductive behavior, antler cycle and group size. Thus, fecal samples, behavioral data and observations of antler status were collected at monthly intervals during 1 year from free-ranging Pampas deer stags (three radio-collared individuals and 15 random individuals) living in Emas National Park, Brazil (18°S latitude). Fecal steroids were extracted using 80% methanol and steroid concentrations were quantified by a commercial enzyme immunoassay (EIA). Fecal testosterone concentrations peaked in December–January (summer), March (early autumn) and in August–September (winter–spring), with minimal values from April–July. Reproductive behavior had two peaks, the first in December–January, characterized by predominately anogenital sniffing, flehmen, urine sniffing, chasing and mounting behavior, and the second peak in July–September (behavior primarily related to gland marking). There were significant correlations between fecal testosterone and reproductive behavior ( r = 0.490), and between fecal testosterone and antler phases ( r = 0.239). Antler casting and regrowth occurred under low testosterone concentrations, whereas velvet shedding was associated with high concentrations of testosterone. We inferred that Pampas deer stags exhibited a seasonal cycle that modulated sexual behavior and the antler cycle, and we concluded that fecal steroid analysis was a practical and reliable non-invasive method for the evaluation of the endocrine status of free-ranging Pampas deer.

Effects of gold on testicular steroidogenic and gametogenic functions in immature male albino rats

The present study was undertaken to evaluate the effects of gold chloride, a metallic earth salt, on steroidogenic and gametogenic functions of testis in immature rats. Immature rats of Wistar strain, were injected (s.c.) with gold chloride at the dose of 0.3 mg and 0.5 mg/kg body weight/day for 26 days. All the treated animals along with the vehicle-treated controls were sacrificed 24 hours after last injections. Testicular steroidogenic activity was evaluated by measuring the activities of two steroidogenic key enzymes, Δ 5-3β-hydroxysteroid dehydrogenase (Δ 5-3β-HSD) and 17-β hydroxysteroid dehydrogenase (17-β HSD). Gametogenic capacity was determined by counting the number of germ cells at stage VII of seminiferous cycle. Plasma levels of testosterone (T) was measured by radioimmunoassay (RIA). Administration of gold chloride at a dose of 0.3 mg/ kg body weight for 26 days led to insignificant changes of testicular Δ 5-3β-HSD,17β-HSD activities and gametogenesis along with plasma T. In contrast 0.5 mg gold chloride treatment for 26 days caused a significant increase in plasma T (p < 0.001) along with stimulation of testicular Δ 5-3β-HSD activity (p < 0.001) and 17β-HSD activity (p < 0.001). Gametogenic activity exhibited a significant increase in the number of step 7 spermatids (7Sd) (p < 0.001) at stage VII of seminiferous cycle when compared to control. The results of our experiment suggest that gold chloride treatment might be associated with significant stimulatory effects on testicular activities. Furthermore, since hormonal changes, altered steroidogenic enzymes and gametogenic activities were evident to a specific dose of gold chloride treatment, our data may have some clinical implication on the stimulation of fertility.

Seasonal variation in the endocrine–testicular function of captive jaguars ( Panthera onca)

Captive adult male jaguars ( Panthera onca) from two locations in southeast Brazil were studied to evaluate the effects of season on endocrine and testicular function. For assessment of testicular steroidogenic activity, androgen metabolite concentrations were measured in fecal samples collected one to three times per week over 14 ( n=4), 9 ( n=1) or 7 months ( n=1). To assess seasonality, data were grouped by season (summer: December–February; autumn: March–May; winter: June–August; spring: September–November). Additionally, samples collected in the dry season (March–August) were compared with those collected in the wet season (September–February). There were no differences ( P>0.05) in fecal androgen concentrations in samples collected in spring, summer, autumn, and winter (480.8±50.4 ng/g, 486.4±42.0 ng/g, 335.4±37.7 ng/g, and 418.6±40.4 ng/g dry feces). However, there were differences ( P<0.05) in fecal androgen concentrations between the dry and wet seasons (380.5±28.0 ng/g versus 483.9±32.3 ng/g dry feces). Sperm samples, collected from all males twice (approximately 6 months apart) were similar; mean (±S.E.M.) motility, concentration and morphology were 57.0±4.5%, 6.3±2.4×10 6 ml −1, and 60.8±3.1%, respectively. In conclusion, androgen metabolite concentrations in the captive male jaguar were not affected by season, but there was a difference between the wet and dry periods. Further research is needed to verify these results.

Testicular toxicity in sodium fluoride treated rats: association with oxidative stress

This study examined the effect of sodium fluoride, a water pollutant important through the world, including India, on testicular steroidogenic and gametogenic activities in relation to testicular oxidative stress in rats. Sodium fluoride treatment at 20 mg/kg/day for 29 days by oral gavage resulted in significant diminution in the relative wet weight of the testis, prostate, and seminal vesicle without alteration in the body weight gain. Testicular Δ 5,3β-hydroxysteroid dehydrogenase (HSD) and 17β-HSD activities were decreased significantly along with significant diminution in plasma levels of testosterone in the fluoride-exposed group compared to the control. Epididymal sperm count was decreased significantly in the fluoride-treated group and qualitative examination of testicular sections revealed fewer mature luminal spermatozoa in comparison to the control. The seminiferous tubules were dilated in treated animals. Fluoride treatment was associated with oxidative stress as indicated by an increased level of conjugated dienes in the testis, epididymis, and epididymal sperm pellet with respect to control. Peroxidase and catalase activities in the sperm pellet were decreased significantly in comparison to the control. The results of this experiment indicate that fluoride at a dose encountered in drinking water in contaminated areas exerts an adverse effect on the male reproductive system and this effect is associated with indicators of oxidative stress.

Seasonal analysis of semen characteristics, serum testosterone and fecal androgens in the ocelot ( Leopardus pardalis), margay ( L. wiedii) and tigrina ( L. tigrinus)

Captive adult male ocelots ( Leopardus pardalis, n=3), margays ( L. wiedii, n=3) and tigrinas ( L. tigrinus, n=4) in two locations in southern Brazil were studied for 14 consecutive months to evaluate the effect of season on testicular function. Reproductive evaluations, including testicular measurements, electroejaculation and blood collection were conducted monthly. Fecal samples were collected weekly for androgen metabolite analysis to assess testicular steroidogenic activity. Ocelots had the highest number of motile spermatozoa in the ejaculate (114.7±15.8×10 6; P<0.05), the highest percentage of morphologically normal spermatozoa (82.4±1.2%; P<0.05) and the highest concentration of fecal androgens (1.71 vs. 0.14 μg/g; P<0.05). Margays and tigrinas had lower numbers of motile spermatozoa (23.4±2.8×10 6, 74.2±8.9×10 6, respectively), lower percentages of morphologically normal spermatozoa (57.4±2.8, 59.2±3.5%, respectively), and lower fecal androgen concentrations (0.15±0.01, 0.23±0.01 μg/g, respectively). Serum testosterone concentrations were similar among the three species. Fecal androgen concentrations were not affected by season, with the exception of the ocelot where concentrations were higher ( P<0.05) in the summer. Ejaculates were collected throughout the year; however, peaks in average sperm production were observed during the summer for all species. In summary, this study has identified several species differences in male testicular traits among ocelots, margays and tigrinas. Results of longitudinal reproductive assessments suggest males of each species are capable of breeding throughout the year.

TESTICULAR GAMETOGENIC AND STEROIDOGENIC ACTIVITIES IN CYCLOPHOSPHAMIDE TREATED RAT: A CORRELATIVE STUDY WITH TESTICULAR OXIDATIVE STRESS

ABSTRACTThe present work examined the changes in testicular activities in relation to testicular oxidative stress in cyclophosphamide as well as human chorionic gonadotrophin (hCG) co-treated cyclophosphamide treated Wistar strain rats. Testicular activities were evaluated by the quantification of spermatogenesis and by the measurement of steroidogenic key enzyme activities along with plasma levels of testosterone. Testicular oxidative stress in relation to cyclophosphamide treatment was monitored by the study of products of free radicals like conjugated dienes and malondialdehyde (MDA) as well as the activity of testicular antioxidant enzymes like peroxidase and catalase. Cyclophosphamide treatment at the dose of 5 mg/kg body weight/day for 28 days resulted a significant diminution in the activities of testicular Δ5, 3β-hydroxysteroid dehydrogenase (Δ5, 3β-HSD), 17β-hydroxysteroid dehydrogenase (17β-HSD) activities, plasma level of testosterone along with significant reduction in the number of germ cells at stage-VII of spermatogenesis. Levels of testicular MDA and conjugated dienes both were elevated whereas testicular peroxidase and catalase activities both were inhibited significantly in cyclophosphamide treated rats in comparison to control. After hCG co-administration at the dose of 5 I.U./kg body weight/day for 28 days in cyclophosphamide treated rats resulted a significant protection in the activities of testicular peroxidase and catalase along with significant decrease in the levels of MDA and conjugated dienes to the control level. Moreover, the testicular steroidogenic key enzyme activities and spermatogenesis along with plasma levels of testosterone were restored to the control level. Therefore, it may be concluded that there is a correlation between testicular steroidogenic activities as well as spermatogenesis and testicular oxidative stress in cyclophosphamide treated rats. Moreover, as restoration of plasma testosterone to the control level is noted in hCG co-treated cyclophosphamide treated rat, therefore, the results suggest that testosterone may be the key regulator for this correlation.

Reproductive endocrine responses to photoperiod and exogenous gonadotropins in the pallas' cat (Otocolobus manul)

AbstractFecal samples were collected for 14–26 months from three male and six female Pallas' cats (Otocolobus manul) to examine gonadal steroidogenic activity in response to changes in photoperiod and treatment with exogenous gonadotropins. Females exhibited a seasonal anestrus from May–December, excreting consistently low concentrations of fecal estrogens (overall mean, 50.2±8.5 ng/g). During the breeding season (January–April), baseline fecal estrogen concentrations were higher, averaging 128.4±18.9 ng/g, with peak concentrations ranging from 455.8–909.6 ng/g. Interpeak intervals in estrogen excretion ranged between 7 and 21 days, with an average estrous cycle length of 14.3±1.7 days. Two females became pregnant after natural mating, with overall luteal progestogen concentrations averaging ∼40 μg/g throughout gestation. Fecal estrogens increased in mid‐gestation, peaking just before birth. Induction of follicular development with eCG (100–300 IU, i.m.) resulted in an increase in fecal estrogens (peak range, 263.1–1198.1 ng/g), followed by a postovulatory increase in fecal progestogens (overall mean, 41.1±11.9 μg/g) after hCG (75–150 IU, i.m.). Despite apparently normal ovarian responses, none of the females conceived after artificial insemination (AI). The gonadotropin‐induced nonpregnant luteal phase lasted 49.8±5.3 days (range, 30–60 days), whereas gestation lasted ∼70 days. In the male Pallas' cat, fecal androgens were elevated from November–April (overall mean, 352.3±30.3 ng/g) compared with nadir concentrations during the rest of the year (82.1±3.3 ng/g). Entrainment of seasonality to photoperiod was demonstrated by stimulation of gonadal steroidogenic activity in cats exposed to increasing artificial light during natural (nonbreeding season) and artificially induced short‐day photoperiods. In summary, reproduction in Pallas' cats is highly seasonal and photoperiod‐dependent. Females exhibit elevated baseline and peak fecal estrogen concentrations for 3–4 months during late winter/early spring. Testicular steroidogenic activity precedes the rise in female estrogen excretion by about 2 months, presumably to ensure maximal sperm production during the breeding season. Zoo Biol 21:347–364, 2002. Published 2002 Wiley‐Liss, Inc.

Seasonal Changes in Testicular Steroidogenesis and Spermatogenesis in a Northern Fur Seal, Callorhinus ursinus.

Seasonal changes in testicular steroidogenesis and spermatogenesis were studied in a captive male northern fur seal, Callorhinus ursinus, of Izu-Mito Sea Paradise. Under anesthesia, monthly blood samplings and testicular biopsies at intervals of 3 months were performed to measure serum testosterone concentrations by radioimmunoassay and to observe spermatogenic activity histologically and the immunolocalization of steroidogenic enzymes. Histological observation of testes revealed full spermatogenesis, including spermatogonia to spermatozoa in the seminiferous epithelium in June and a limited generation of germ cells such as spermatogonia and primary spermatocytes in September and December. The seminiferous tubule diameter and serum testosterone concentrations showed maximum fluctuations corresponding to full spermatogenic activity in June. Three kinds of steroidogenic enzymes, P450scc, 3βHSD and P450c17, which are necessary for androgen synthesis, were immunolocalized in Leydig cells, and P450arom, the key enzyme for estrogen synthesis, was immunolocalized in spermatogonia in the testes in all 3 seasons. These results indicate a definite seasonality in high-level testicular steroidogenic and spermatogenic activity of this northern fur seal during the breeding season in spite of there being no changes in the immunostaining of intratesticular steroidogenic enzymes throughout the year.

Fecal androgen metabolite analysis for noninvasive monitoring of testicular steroidogenic activity in felids

Limited data are available on long-term, seasonal changes in testicular steroidogenic activity in nondomestic felids, primarily because of the difficulties associated with longitudinal blood sampling (e.g., handling, restraint, anesthesia). Therefore, a noninvasive approach for assessing testicular androgen production was developed using the domestic cat (Felis catus) as a model. Two adult males were injected i.m. with 4 μCi14-testosterone to determine the time course and relative proportions of androgen metabolites excreted in urine and feces. Peak urinary radioactivity was detected 13 and 19 hr postinjection and accounted for ∼8% of the total radioactivity recovered. High performance liquid chromatography (HPLC) analysis detected multiple polar urinary metabolites, none of which eluted with the 3H-testosterone reference tracer. The majority of urinary testosterone metabolites consisted of nonenzyme-hydrolyzable, water-soluble (presumably conjugated) forms. In feces, radioactivity was detected in the first sample collected at 22 hr postinjection for both males, although peak metabolite excretion in one male was not observed until 61 hr postinjection. HPLC analysis detected several fecal metabolites consisting primarily of nonhydrolyzable, water-soluble forms (84.4 ± 0.9%) with some ether-soluble forms (15.6 ± 0.9%). None of the fecal androgen metabolites were associated with free testosterone. However, one or more of the water-soluble fecal metabolites was quantifiable using a commercially available testosterone radioimmunoassay. The biological relevance of this immunoactivity was confirmed in the domestic cat; concentrations were high in adult, intact males and nondetectable in intact females and castrated males and females. In addition, fecal androgen concentrations in a male Pallas' cat (Felis manul) exhibited seasonal fluctuations that corresponded with parallel changes in serum testosterone and ejaculate quality. These data indicate that testicular steroidogenic activity can be monitored non invasively in felids, providing a potentially valuable tool for endangered felid management to: (1) assess pubertal status, (2) determine the influence of season on reproduction, and (3) diagnose possible causes of sub- or infertility. © 1996 Wiley-Liss, Inc.

Effects of Nitrofurantoin and Cadmium Chloride on Spermatogenetic Activity in an Avian Pest, the Yellow-throated Sparrow(Petronia xanthocollis Burton).

Oral administration of nitrofurantoin (200mg/kg body weight daily for 5 days) caused reduction in testis weight, seminiferous tubular diameter, and secondary spermatocyte and spermatid populations in the yellow-throated sparrow (Petronia xanthocollis, Burton). Spermatozoa bacame less abundant, but Leydig cell nuclear area, 3β-HSDH activity and sialic acid content of the testis remained unaltered after treatment. Single intraperitoneal injection of cadmium chloride (0.05mg/kg body weight) failed to produce any perceptible effect on the testis of the yellow-throated sparrow.It is suggested that nitrofurantoin has an antispermatogenetic effect in the yellowthroated sparrow. But cadmium chloride, at least with the dose administered, has no effect on the testis of this avian species. Moreover, both the chemosterilants have no effect on gonadotrophic activity or testicular steroidogenic activity in the yellow-throated sparrow.

Effects of follicular fluid administration on serum bioactive and immunoreactive FSH concentrations and compensatory testosterone secretion in hemicastrated adult rats.

In adult rats, removal of one testis (hemicastration) results in an elevation of serum follicle-stimulating hormone (FSH) concentrations and a compensation in testosterone secretion by the remaining testis without a corresponding increase in testis size. To determine whether changes in FSH secretion and compensatory androgen production are related, serum testosterone concentrations were measured after inhibin-rich porcine follicular fluid was administered twice daily for 4 days to block the hemicastration-induced rise in FSH. Both serum immunoreactive FSH (immuno-FSH) and bioactive FSH (bio-FSH) concentrations were increased 4 days after hemicastration. The significant increase in serum immuno-FSH in hemicastrated animals was prevented by follicular fluid administration, whereas the serum bio-FSH activity and biologic to immunologic (B/I) ratios were increased in follicular fluid-treated animals. The follicular fluid-induced reduction in serum immuno-FSH had no effect on serum testosterone secretion in hemicastrated rats. Serum inhibin concentrations were reduced 27% in hemicastrated rats compared with intact controls, while administration of exogenous follicular fluid increased serum inhibin concentrations. An elevation in serum immuno-FSH secretion after hemicastration apparently is not required for the compensatory testosterone response. However, the observation of increased bio-FSH in hemicastrated and follicular fluid-treated animals raises questions about the importance of FSH quality (bioactivity), rather than quantity, for controlling testicular steroidogenic activity.

Effect of long term diazepam administration on testicular benzodiazepine receptors and steroidogenesis

We evaluated the effect of acute and chronic diazepam administration on testicular peripheral type benzodiazepine receptors (PBZD-R), serum testosterone and LH levels and the “in vitro” androgen production in response to Ro 5-4864, a PBZD-R agonist. The chronic diazepam treatment induced a significant fall in plasma testosterone concentration while LH levels remained unchanged. The number of PBZD-R was reduced by 37% and low concentrations (10 −8 − 10 −6M) of Ro 5-4864 failed to stimulate “in vitro” androgen production. The acute diazepam administration caused a significant increase in plasma testosterone levels while no changes were observed in LH concentrations and testicular PBZD-R. These results further suggest a modulatory role of PBZD-R on testicular steroidogenic activity.

Testosterone and LH concentrations in the male Angora goat during puberty

Fifteen Angora male kids were used in order to investigate long-term reproductive endocrine changes associated with testis size, liveweight and season in a study of puberty and duration of the first breeding season. Blood samples were collected at weekly intervals; testis size and liveweight were recorded at 2-week intervals from post-weaning through puberty. With respect to the testosterone and LH concentrations and testis and body growth rates, that is, onset of puberty, two different groups of kids were distinguished (groups A and B). Testosterone and LH levels were significantly higher ( P<0.01) in group A than in group B during the breeding season, as were testis size and body weight, reflecting that group A animals reached puberty earlier (∼ 178 ± 12 days of age). The high levels of testosterone (4.09±1.78 ng/ml) found in autumn were evidently a result of increased testicular steroidogenic activity (testicular responsiveness to LH). The elevation in testosterone and LH levels was accompanied by decreasing daylength and temperature, and increasing humidity. It thus appears that in male kids the onset of puberty and sexual maturation are individually variable.

Intratesticular Control Of Steroidogenesis

Men are men because of testosterone, and the effects of this hormone are evident in virtually every organ or tissue in a normal adult man. Because testosterone is a classical endocrine hormone with effects throughout the body, many endocrinologists will have failed to realize that, in terms of its effects on fertility, the primary role of testosterone is not endocrine but paracrine, as it is the local action of testosterone on spermatogenesis which determines fertility. When looked at from this perspective it is logical to question the traditional endocrine teaching which states that testosterone secretion is controlled solely by pituitary luteinizing hormone (LH). Certainly, the levels of testosterone and LH in peripheral blood show a close relationship, but it is not the level of testosterone in peripheral blood which determines fertility. If the primary role of testosterone is within the testis, then it is not unreasonable to expect that local mechanisms may exist to regulate the intratesticular levels of this steroid. The object of this review is to examinecritically the evidence for such mechanisms, their possible nature and their physiological and clinical significance (if any). Before reviewing the data on intratesticular control of steroidogenesis it is essential to place it in perspective. To do this, three principal questions need to be answered: (I) Why might intratesticular mechanisms for local control of testosterone production be required? (2) What is the role (or roles) of testosterone within the testis? A proper understanding of how testosterone controls spermatogenesis is essential if the local regulation of testosterone production is to be evaluated from a physiological perspective. (3) What are the constraints or problems relating to studies on the intratesticular control of steroidogenesis? It is essential to understand the potential limitations of studies on this subject so that a reasoned interpretation of the results can be made. Most relevant data is derived from studies in uitro, and the relationship of such data to the situation in uivo is often difficult to establish.

Effects of lithium chloride on testicular steroidogenic and gametogenic functions in mature male albino rats

The present study was undertaken to evaluate the effects of lithium, an antimanic drug, on steroidogenic and gametogenic functions of testis in the laboratory rat. Adult male rats of Wistar strain maintained under standard laboratory conditions (L:D. 14h: 10h), were injected (S. C) with lithium chloride at the dose of 0.1 mg, 0.2 mg and 0.4 mg/100 g body weight/day for 21 days. All the treated animals along with the vehicle treated controls were sacrificed 24 hours after the last injections. Testicular steroidogenic activity was evaluated by measuring the activities of two steroidogenic key enzymes, Δ 5 −3 β hydroxysteroid dehydrogenase (Δ 5 −3 β -HSD) and 17β hydroxysteroid dehydrogenase (17 β −HSD). Gametogenic capacity was determined by counting the number of germ cells at stage VII of seminiferous cycle. Plasma levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL) and testosterone (T) were measured by radioimmunoassay (RIA). Administration of lithium chloride at a dose of 0.1 mg/100g body wt. for 21 days led to insignifiant changes of plasma FSH, LH, PRL and T along with unaltered activities of testicular Δ5 −3β −HSD, 17 β−HSD activities and gametogenesis. In contrast, 0.2 mg of lithium treatment for 21 days causes a significant reduction of plasma FSH (P < 0.01), LH (P < 0.001), PRL (P < 0.001) and T (P < 0.001) along with inhibition of testicular Δ 5 −3 β −HSD activity (P < 0.01) and 17β −HSD activity (P < 0.001). Gametogenic activity does not exhibits any significant reduction in the number of preleptotene spermatocytes (PLSc) and midpachytene spermatocytes (mPSC) while significant reduction in the number of spermatogonia A (Asg) (P < 0.01) and Step 7 spermatids (7Sd) (P < 0.001) were observed at stage VII of seminiferous cycle when compared to control. The degree of detrimental effects of lithium on testicular activity became more prominent at the dose of 0.4 mg/100g body wt. The results of our experiments suggest that lithium administration might be associated with significant adverse effects on testicular activities. Furthermore, since hormonal changes and altered gametogenic activities were evident when plasma lithium concentration was below or within the therapeutic range, our data may have some potential clinical implications.