Melatonin prevents decrease in plasma Prl and LH levels in male hamsters exposed to a short photoperiod

Treatment of male golden hamsters with melatonin injections can cause a decrease in plasma gonadotropin and Prl levels and induce testicular regression. However, administration of melatonin via subcutaneously implanted Silastic capsules can prevent short photoperiod from causing the testes to regress. In order to explain this effect of melatonin capsules, we examined plasma Prl, LH and FSH levels in pinealectomized and sham-operated hamsters in which empty or melatonin-filled Silastic capsules had been implanted. After implantation, the hamsters were transferred to a short photoperiod (5 h L:19 h D) for 9 weeks. Both pinealectomy and melatonin completely prevented the decline in plasma Prl and LH levels and in the weight of the testes and the seminal vesicles. Moreover, testicular weight and plasma Prl and LH levels were higher in pinealectomized animals given melatonin capsules than in pinealectomized animals given empty capsules. In order to obtain some indication whether melatonin may affect testicular function directly, we have examined the influence of melatonin on the production of testosterone by hamster testes in response to hCG in vitro. Addition of 0.2. 10 or 500 ng of melatonin per ml of incubation medium had no effect on testosterone production in this system. It is concluded that melatonin capsules prevent regression of the male reproductive system in short photoperiod, most likely by preventing the decline in plasma Prl and LH levels and that these effects of melatonin are not mediated through or dependent on the pineal.     

Antiandrogenic activities of Glycyrrhiza glabra in male rats

Abnormal levels of androgens cause many diseases like benign prostatic hyperplasia and hormone dependent cancers. Although the reduction in serum testosterone (T) by Glycyrrhiza glabra has been reported, its effects on seminal vesicle (SV) and prostate tissues have never been reported. This study was carried out to investigate different aspects of antiandrogenic properties of this plant. Immature male rats were divided into five groups ( n  = 7): castrated rats without any treatment received only vehicle; castrated rats plus T replacement; three castrated groups with T replacement plus various doses of G. glabra extract (75, 150 and 300 mg/kg). All of the injections were carried out once daily in subcutaneous manner for 7 days. On the eighth day, blood samples were collected for total T measurement. Ventral prostate (VP), SV and levator ani muscle were dissected and weighed. Slides prepared from prostate were assessed histologically. The variation in the relative and absolute volume of the prostate tissue compartments was determined. Those receiving the doses of 150 and 300 mg/kg showed a significant reduction ( p  <   0.05) in prostate weight, total T and VP epithelium/stroma ratio (V/V). These results in SV and levator ani were shown in response to 300 mg/kg of extract. Increasing in T metabolism, down-regulation of androgen receptors or activation of oestrogen receptors could be involved mechanisms. This study showed that alcoholic extract of G. glabra has antiandrogenic properties.     

Short-Term Effects of an LHRH-Agonist alone or in Combination with Testosterone Propionate or Indomethacin on Rat Testes

The treatment of adult male Wistar rats with a LHRH-agonist (lutrelin Wyeth/WY 40972) resulted in severe damage of the seminiferous tubules as well as in remarkable changes of the blood vessels within 24 hours. First striking signs of alterations within the blood vessels were already found 6 hours after the injection of lutrelin: the blood vessels were almost totally filled with leucocytes. Neither the effects on the germinal epithelium nor the effects on the blood vessels were prevented by the simultaneous treatment with 3 mg testosterone propionate (TP). The treatment with indomethacin, however, clearly antagonized both events. The complete inefficiency of TP to overcome the inhibitory effects of lutrelin on the testes does argue against an androgen deficiency as the primary cause. The results obtained with indomethacin strengthen the hypothesis, that the early deleterious effects of LHRH-agonists on the germinal epithelium of the rat are primarily caused by circulatory disturbances in the testes and that prostaglandins may act as mediators.     

Some effects of furazolidone on the testis and plasma levels of testosterone, luteinizing hormone and prolactin in mature male turkeys

Adult male turkeys were treated orally with furazolidone at doses of 1, 2.5, S or 20 mg/kg for 14 days and their plasma analysed for luteinizing hormone (LH), testosterone and prolactin (PRL) concentrations before, during and after treatment. At 20 mg/kg the drug produced a significant decrease in the plasma levels of LH and testosterone at the end of treatment, whereas at 5 mg/kg the drug had no significant effect. Prolactin concentrations were unaffected by any of the drug doses used. Intramuscular injection of luteinizing hormone releasing hormone (LHRH) at a dose of 5 μg/kg produced after 30 min a significant rise in plasma levels of LH, an effect that was decreased significantly by treatment with 20 mglkg furazolidone. Incubation of normal turkey semen with graded doses of furazolidone or nitrofura-zone for up to 30 min resulted in a dose- and time-dependent decrease in sperm motility. At a concentration of 20 mg/ml a complete absence of sperm motility was observed after incubation with either drug, although, on the whole, nitrofurazone seemed more potent than furazolidone as a sperm-immobilizing agent. Histological changes occured in the 20 mg/kg group and consisted of a decrease in spermatocyte production, corrugation of sperm cell nuclear envelopes and distention of the endoplasmic reticulum of elongate spermatids. It is concluded that furazolidone depresses pituitary LH output but may, in addition, directly affect spermatogenesis and sperm motility.     

Indomethacin decreases both prolactin binding and membrane fluidity of ventral and dorso-lateral lobes of rat prostate gland

The objective of these studies was to examine the effects of in vivo treatment with indomethacin, a prostaglandin synthesis inhibitor, on prolactin binding activity and fluidity in membrane preparations of rat prostate gland. Adult male rats were treated with vehicle or either of two doses of indomethacin (3.8 μg/g body weight or 7.5 μg/g body weight) every 8 hr for 1, 2, and 3 days. Indomethacin treatment decreased prolactin binding in rat ventral and dorso-lateral lobes of prostate gland in a time and dose-dependent fashion. In ventral prostate membranes the higher dose of indomethacin decreased prolactin binding by approximately 80% after 3 days of treatment. Prolactin binding to membrane preparations from dorso-lateral prostate gland of control animals was 10% of that observed for ventral prostate and decreased to undetectable levels within 24–48 hr after the start of indomethacin treatment. Scatchard analysis of the prolactin binding of ventral prostate indicated that indomethacin treatment decreased the number of prolactin binding sites rather than the apparent affinity constant. Prostatic membrane fluidity was measured by a fluorescence polarization technique. Dorso-lateral prostate membrane preparations were found to have a higher membrane fluidity than those observed for ventral prostate membranes. The effects of indomethacin on membrane fluidity paralleled that of prolactin binding. Both ventral and dorso-lateral prostatic membrane fluidity decreased after indomethacin treatment in a time and dose-dependent manner. These simultaneous effects of indomethacin on prostatic prolactin binding and fluidity suggest that these phenomena are interrelated and that prostaglandins are involved in the maintenance of prolactin receptors in vivo.     

Influence of Thyroidectomy on Glycolytic Enzymes in Seminal Vesicles and Ventral Prostate

The effect of thyroidectomy on phosphohexoseisomerase (PHI) and lactate dehydrogenase (LDH) activities in the seminal vesicles and ventral prostate of rats has been investigated. Following long term thyroidectomy the activities of PHI and LDH declined 28% and 40%, respectively, in the ventral prostate when compared to the values for normal rats. However, both PHI and LDH activities were elevated to 27% and 33%, respectively, in the seminal vesicles of thyroidectomized rats. The data reported in this communication are consonant with the view that an altered thyroid state may have a definite influence on androgen-regulated glycolytic enzyme activities in the male accessory organs, thereby indirectly affecting the secretory activities of these tissues.     

Dose-Dependent Effects of Milk Lipids on Sex Hormone and Blood Lipid Levels in Male Mice

Dosisabhängige Einflusse von Milchlipiden auf Sexualhormon- und Blutlipid-Werte bei männlichen Mäusen
Im Tierexperiment wurde 21 Tage alten männlichen Mäusen eine Kost zugeführt, die aus Vollmilchpulver bestand; diese Kost führte zu einem dosisabhängigen Anstieg des Samenblasengewichtes. In dem Maße, wie die Lipide in der Kost anstiegen, stieg der Blutcholesterinwert. Die Triglyceride waren hoch und umgekehrt verwandt zur Lipid-aufnahme. Die peripheren Androgenkonzentrationen fielen mit steigender Lipidauf-nahme und einem Anstieg des Gewichtes der Samenblasen ab; das bedeutet nach Meinung der Autoren möglicherweise eine Verschiebung des Hormons zum Targetorgan-Gewebe.     

Short Term Metabolic Effects of the Anti-Fertility Agent, Gossypol, on Various Reproductive Organs of Male Mice

In order to evaluate the short term metabolic effects of gossypol on the testes as well as any possible effects on the secondary sex organs, Balb C mice were injected subcutaneously with various doses of gossypol (0.25-25.0 mg/kg body weight) in corn oil for 10 days. Wet weights of several different secondary sex reproductive organs decreased during gossypol treatment. However, wet weights of the testes during treatment remained equal to or greater than control values. Following 10 days of gossypol treatment, incorporation of [³H]thymidine or [³H]amino acids into trichloroacetic acid precipitable macromolecules was inhibited in the seminal vesicles and ventral prostates normalized to either DNA or wet weight. Treatment with gossypol also had an inhibitory effect on epididymal sperm count at the two highest doses.
These results demonstrate that gossypol will decrease sperm count at high dose levels after treatment of male mice for as short as 10 days. However, its overall effects are not limited to the testes and spermatogenesis but, in addition, it has dramatic inhibitory effects on protein and nuclei acid metabolism in the secondary sex organs.     

Effects of hyperprolactinemia on the accessory sexual organs of the male rat

The growth-promoting effect of prolactin on the ventral prostate lobe, the anterior prostate lobe (or coagulating gland), and seminal vesicles has been studied before, during and after puberty in rats up to 5 months of age. Pituitaries from female rats were grafted under the renal capsule of 23-26-day-old male rats. Within 1/2 month substantial (five- to ten-fold) hyperprolactinemia occurred followed by a gradual decline; levels were still high 4 months after grafting. A statistically significant increase in the weight of the seminal vesicles and the ventral and anterior prostate lobes was observed 1 month after implantation. This effect was only maintained for the seminal vesicles during the next 3 months. Hyperprolactinemia did not influence testosterone metabolism. In the ventral prostate lobe, 1 month after grafting, the nuclear androgen receptor content increased, whereas the cytosolic androgen receptor content decreased. These results suggest that the growth-promoting effect of prolactin, on the ventral prostate lobe of the rat, is brought about by an increased translocation of the androgen receptor.     

Foetal testicular steroidogenesis and responsiveness to LH in freemartins and their male co-twins

Foetal gonads were obtained from 1) 8 male foetuses that were co-twin to freemartins, 2) 8 isosexual twins, 3) 59 singletons of 45–75 days of gestations, 4) 5 isosexual and 5 male co-twins of 90–120 days and 5) 5 freemartins at 70–120 days of gestation. The gonads were incubated in supplemented medium 199 for 24 h in the absence or presence or LH and the testosterone and progesterone produced measured by RIA. During the time of sexual differentiation (45–75 days) the testes of the male co-twins produced significantly less testosterone than testes from isosexual or singletons of the same age. Testes of foetuses older than 90 days were refractory to LH-stimulation, but freemartin ovaries and testes from their male co-twins continued to respond to LH with increased testosterone production. No significant differences in progesterone production were detected amoung co-twins, isosexual twins or singletons at any age. We conclude that the testes of the male twin that is co-twin to a freemartin displays abnormal steroidogenesis. This may be related to reports of abnormal testes after birth in males co-twin to free-martins.     

Hypothalamic Control of the Testis in the Ram

Adult Soay rams were maintained under an artificial lighting schedule which induced a seasonal cycle in testicular activity every 8 months. At 3 stages of the testis cycle (regressed, developing and active) the episodic nature of LH secretion was assessed from blood samples collected at frequent intervals. At the same time the LH release in response to 3 doses of LH-RH (50, 250 and 1000 ng) was measured. The endogenous release of LH-RH was then deduced from the episodic pattern of LH secretion using the dose response to synthetic LH-RH as a standard. The result showed that in the ram LH-RH secretion is episodic, and the hypothalamus regulates release by changing both the frequency and magnitude of the episodes of secretion.     

Basal serum testosterone as an indicator of response to clomiphene treatment in human epididymis,seminal vesicles and prostate

The present study was designed to determine the response of human epididymis, seminal vesicles and prostate function after a 5-day course of clomiphene citrate in men attending an infertility service. In 45 men, the secretions of the epididymis, seminal vesicles and prostate were assessed by measurements of seminal alpha-glucosidase, fructose and acid phosphatase, respectively. Subjects were classified as normal or abnormal: abnormal men were defined as those who either had history of a sexually transmitted disease (STD), leukocytospermia, hypoandrogenism, or a low response of Leydig cells to clomiphene stimulation; and normal subjects were those who did not have these conditions. Mean serum testosterone luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels were significantly increased after the short course with clomiphene citrate. After clomiphene citrate stimulation, the men in the normal group showed significantly increased marker levels of the seminal vesicles (P < 0.02) and prostate (P < 0.05), but not of the epididymis (P : NS). Men classified as abnormal showed no response according to the markers of the seminal vesicles and epididymis. Men with history of STD and abnormal basal values of acid phosphatase did not respond to the treatment. Men with history of STD but normal basal values of seminal acid phosphatase increased significantly in their levels of seminal acid phosphatase after clomiphene stimulation (P < 0.02). Multivariate analysis showed that the basal serum testosterone level was the only variable in predicting the probability of response to the clomiphene in terms of true-corrected seminal fructose, seminal acid phosphatase and seminal alpha-glucosidase levels. In fact, a high response of the seminal vesicles was observed in men with the highest basal serum testosterone levels (0.45 +/- 0.17; coefficient of regression +/- standard error; P < 0.018). However, a high response in terms of seminal acid phosphatase (P < 0.004) or alpha-glucosidase (P < 0.037) was observed in men with low basal serum testosterone levels. In conclusion, in the normal men, true-corrected fructose and acid phosphatase but not alpha-glucosidase in semen increased after duplicate androgen stimulation. An absence of response was observed in cases with history of STD/leukocytospermia or hypoandrogenism.     

The hypophyseal-testicular axis and sex accessory glands following chemical sympathectomy with guanethidine of pre-pubertal to mature rats

Summary.  Selective chemical sympathectomy of the internal sex organs of prepubertal to mature male Wistar rats was performed by chronic treatment with low doses of guanethidine. Plasma testosterone and luteinizing hormone and the intratesticular level of testosterone were determined. The weight and fructose content of seminal vesicle and ventral prostate were also investigated. The results showed that sympathetic innervation is related to the control of the hypophyseal-testicular axis as well as to the growth and potential secretory activity of the male sex accessory glands.     

8～17周岁男性FSH、LH、PRL、E2、T的调查分析

目的:通过对8~17周岁男性青少年FSH、LH、PRL、E2、T的测定,了解不同年龄的FSH、LH、PRL、E2、T的变化。方法:对627例体检合格的8~17周岁男性血清使用Access全自动微粒子化学发光免疫分析仪进行FSH、LH、PRL、E2、T的检测,并使用免疫分析质控液进行质量控制。结果:FSH在8~10周岁处于较低水平,11周岁时开始增高;LH和T在12周岁前处于较低水平,13周岁开始增高;E2在13周岁前较低,14周岁后开始增高(P均<0.01)。结论:男性青少年FSH、LH分别在11、12周岁时明显增高,T在13周岁时明显增高,标志性发育的开始。     

Time course of serum testosterone and luteinizing hormone levels after cessation of long-term luteinizing hormone-releasing hormone agonist treatment in patients with prostate cancer

INTRODUCTION: In order to elucidate the influence of hormone-releasing hormone (LH-RH) agonist therapy cessation on pituitary/testicular function and its clinical implications, we investigated prospectively hormonal (luteinizing hormone: LH; testosterone: T) responses in patients with prostate cancer who received long-term LH-RH 10 agonist therapy. PATIENTS AND METHODS: A consecutive 32 patients who had received LH-RH agonist therapy over 24 months were enrolled. As a baseline, T and LH were measured at the time of LH-RH agonist therapy cessation, monthly for 3 months, and subsequently, every 3 months. RESULTS: The median duration of LH-RH agonist therapy was 30 months (24-87 months) with median follow-up duration of 24 months following cessation. All patients had castrated T levels and suppressed LH levels at baseline. Median duration of castrated T levels following cessation was 6 months. Median time to normalization of T levels was 24 months. LH levels returned to normal within 3 months in all cases. Patients who received androgen deprivation therapy for 30 months or longer required a longer time for recovery of T levels. Patients over 65 years of age showed a statistically significant longer time for recovery of T levels (P=0.0167). CONCLUSIONS: Long-term LH-RH agonist therapy has remarkable effects on serum T level that last for a significant time after cessation, a fact that should be applied to the interpretation of both PSA and serum T levels after cessation of androgen deprivation therapy.     

Binding of seminal vesicle proteins to the plasma membrane of rat spermatozoa in vivo and in vitro

The association of seminal vesicle (SV) proteins with rat spermatozoa has been studied in vivo and in vitro. SV proteins bind to the sperm plasma membrane after ejaculation but are removed progressively from the sperm plasma membrane in the female genital tract. Although some of these remain bound to spermatozoa when they reach the oviducts, they do not seem to be present at the time of fertilization. This could indicate a putative role for these SV proteins in pre-fertilization events. In addition, the binding of SV antigens was studied in vitro. It was observed that the ability to bind SV proteins is gained by the spermatozoa during epididymal maturation, and is first detectable in spermatozoa collected from the cauda epididymis. On the other hand, the binding is regulated by other proteins present in the ejaculate which are secreted by the coagulating glands. Experiments also showed that mouse spermatozoa are able to bind rat SV proteins, indicating that the binding is not a highly species-specific phenomenon.     

Effects of bromocriptine-induced hypoprolactinaemia on the developmental pattern of androgen and LH levels in the male rat

In immature male rats, receiving daily injections of bromocriptine (3 mg/kg bw), serum prolactin (Prl) remains low throughout development. In such hypoprolactinaemic males androgen variables are affected: a) the normally low pre-pubertal serum androgen (testosterone, dihydrotestosterone-T, DHT) is considerably increased, in correlation with a precocious development of the testicular Leydig cell population; b) the peri-pubertal rise of androgen is not prevented, but it is followed by significantly lower post-pubertal T, DHT levels, in correlation with moderately reduced Leydig cell counts and with strongly attenuated growth rates of sex accessory organs. Observed alterations of the post-natal androgen pattern cannot be related to LH changes since developmental LH values remained essentially unaltered. Results are in concordance with a marked age-dependent sensibility of androgen variables to a lack of Prl in the developing male.     

Effect of androgen deprivation on the expression of aquaporins in rat prostate and seminal vesicles

The aim of this study was to investigate the level of secretions of prostate and seminal vesicles and its association with the expression of AQP0, 1, 4, 5, 6 and 8 in castrated rats. Eight‐week‐old male Sprague‐Dawley (SD) rats (n = 18) were randomly divided into control group, castrated rats group and castrated followed testosterone replacement group. Four weeks after surgery, the secretions and expression of AQP0, 1, 4, 5, 6 and 8 of prostate and seminal vesicles were determined. Serum testosterone was significantly lower in castrated groups than in control and testosterone replacement groups (P < 0.05). The level of prostate and seminal vesicle secretions and the expressions of AQP0, 1, 4, 5, 6 and 8 in prostate and seminal vesicles were significantly lower in castrated group than in control and castrated followed testosterone replacement groups (P < 0.05). The decreased prostatic and seminal vesicle secretions in castrated rats may be related to the decrease in AQP0, 1, 4, 5, 6 and 8 in prostatic tissue and seminal vesicles.