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The stimulatory effect of leptin on the neuroendocrine reproductive axis of the monkey.

Leptin acts as a metabolic activator of the neuroendocrine reproductive axis in several rodent species, but whether leptin plays a similar role in primates is unknown. To explore this question, we examined the effects of leptin on gonadotropin and testosterone secretion in male rhesus monkeys that were fasted for 2 days. Mean plasma levels of LH and FSH, LH pulse frequency, and LH pulse amplitude were significantly higher in leptin-treated animals compared with saline-treated controls during the second day of the fast. To identify targets for leptin's action, we used in situ hybridization and computerized imaging to map leptin receptor (Ob-R) messenger RNA (mRNA) distribution. Ob-R mRNA was observed in the anterior pituitary and several areas of the brain, including the arcuate and ventromedial nuclei of the hypothalamus. Ob-R mRNA was coexpressed in both POMC and neuropeptide Y neurons in the arcuate nucleus, whereas little or no coexpression of Ob-R mRNA was evident in GnRH neurons. These results suggest that leptin is a metabolic signal to the reproductive axis in primates and imply that both POMC and neuropeptide Y neurons are involved in mediating leptin's effects in the brain.

Animals↗

Impaired corpus luteum function in ectopic pregnancy cannot be explained by altered human chorionic gonadotropin.

We studied the cause of the low serum progesterone, 17 beta-estradiol, and 17-hydroxyprogesterone levels that occur in women with an ectopic pregnancy. Only women who had been amenorrheic for less than 8 weeks were studied in order to assess corpus luteum rather than placental biosynthesis of these steroids; each woman with an ectopic pregnancy was matched to a woman with a normal intrauterine pregnancy on the basis of serum intact hCG levels within 10% of one another to obviate the influence of different levels of this luteotropic hormone. Every woman with an ectopic pregnancy had lower serum progesterone, estradiol, and 17-hydroxyprogesterone levels than her matched normal pregnant pairmate (median values: progesterone, 27.9 vs. 83.5 mmol/L; estradiol, 0.36 vs. 1.79 nmol/L; 17-hydroxyprogesterone, 4.95 vs. 22.1 nmol/L, respectively; all P less than 0.002). The ratios of intact hCG, measured by immunoradiometric assay, to hCG, measured by a hCG beta-specific RIA, were similar in the two groups. Serum hCG bioactivity was assayed by measuring the ability of serum to stimulate testosterone secretion from mouse Leydig cells. The mean biological to intact immunological hCG ratios were 2.06 +/- 1.39 (+/- SD) for ectopic pregnancy and 1.91 +/- 0.81 for normal pregnancy (P greater than 0.05). The biological hCG to immunoreactive hCG beta ratios were 1.98 +/- 0.75 and 2.02 +/- 0.82, respectively. Serum hCG from both groups of women stimulated cAMP generation by testicular cells similarly. We conclude that the lower serum steroid levels in women with ectopic pregnancy cannot be explained by altered hCG bioactivity. The lower steroid levels may thus reflect a primary defect of the corpus luteum, absence of another stimulator of ovarian steroid biosynthesis, or more subtle alterations in hCG glycosylation which are important in vivo but not assessed by the in vitro bioassay.

Animals↗

Presence of immunoreactive corticotropin-releasing hormone in normal and polycystic human ovaries.

Recently, we demonstrated the presence of immunoreactive (Ir) CRH and its receptors in the rat ovary. To determine whether CRH is also present in human ovaries, we examined ovaries from normal women and patients with the polycystic ovarian syndrome (PCOS). Immunoreactive CRH in normal human ovaries had a similar distribution to that of rat ovarian IrCRH, as determined by immunohistochemistry. Thus, immunoreactivity was intense in the cytoplasm of thecal cells surrounding the ovarian follicles, in luteinized cells of the stroma, and in a subpopulation of cells within the corpora lutea. No IrCRH was present in oocytes of primordial follicles. Polycystic ovaries also had IrCRH in thecal cells; however, CRH immunostaining was less prominent or completely absent from the stroma or the sparsely present corpora lutea and was clearly detected in oocytes of primordial follicles. Using a specific RIA, the IrCRH content in extracts of normal ovaries was higher than that in polycystic ovaries (mean +/- SD, 0.075 +/- 0.02 vs. 0.038 +/- 0.009 pmol/g wet tissue, respectively; P < 0.05). Human follicular fluid samples collected from women undergoing ovarian hyperstimulation for assisted reproduction had low, but detectable, levels of IrCRH (mean +/- SD, 4.975 +/- 1.179 pmol/L), whereas IrCRH was undetectable in concurrently drawn plasma samples. IrCRH detected in normal and polycystic ovaries and in follicular fluid had similar chromatographic mobility to that of rat/human CRH-(1-41) by reverse phase HPLC. We conclude that IrCRH is present in normal human ovaries and follicular fluid, suggesting that this neuropeptide may play a regulatory role in one or more of the various functions of this gonad, such as ovulation and/or luteolysis, through its proinflammatory properties and/or its auto/paracrine regulation of steroid biosynthesis, in analogy to its action on testosterone secretion by the Leydig cell. Its decreased concentration and localization in primary oocytes of polycystic ovaries may be related to the increased androgen biosynthesis by the theca and stroma and/or to the oocyte dysfunction observed in women with the polycystic ovarian syndrome, respectively.

Adolescent↗

The effects of chronic high dose androgen or estrogen treatment on the human prostate [corrected].

Prostate development and disease are androgen dependent. However, the nature of hormonal effects on the prostate of healthy young men is not clear. We, therefore, measured prostate size in males chronically exposed to high doses of androgens (AS; habitual anabolic steroid abusers; n = 15) or estrogens (E; male to female transsexuals; n = 11) and compared the results with those in age-matched healthy eugonadal men without known prostate disorders. Prostate size was measured by planimetric ultrasound as cross-sectional areas and maximal dimensions in three orthogonal dimensions with a 7.5-megahertz B-mode sector scanner biplane in a transrectal transducer at 2.5 mm steps from the base to the apex of prostate. Total prostate volume (TPV) was reconstructed from planimetric sections, central prostate volume (CPV) was calculated by the ellipsoidal formula from the appropriate three maximum dimensions, and peripheral prostate volume was determined by the difference between TPV and CPV. Compared with age-matched controls, TPV was normal (-2%) in AS (P = 0.752) and reduced by 31% in E (P = 0.002), whereas CPV was increased by 20% in AS (P = 0.002) and reduced by 46% in E (P = 0.002), and the ratio of CPV/peripheral prostate volume was increased by 77% in AS (P < 0.001) and decreased by 33% in E (P = 0.047). Blood sex hormone-binding globulin was elevated by nearly 500% in E (P < 0.001), but was reduced by 47% in AS (P = 0.003). Prostate-specific antigen was normal (-6%) in AS (P = 0.799) and decreased by 86% in E (P = 0.002). Prostatic acid phosphatase was increased by 26% in AS (P = 0.007), but was unchanged (-28%) in E (P = 0.106). Total and free testosterone levels were reduced to castrate levels in E, whereas LH, FSH, and total testosterone levels were significantly reduced in AS. We conclude that in the human prostate of young men, CPV is more hormonally sensitive than TPV, and during high dose treatment, CPV is preferentially increased by chronic androgen treatment and decreased by chronic estrogen treatment. The reduction of TPV by estrogens was less than expected if solely attributable to inhibition of endogenous gonadotropin and testosterone secretion, suggesting that estrogens also have a positive effect on the normal human prostate. The reversibility and long term significance of androgen-induced stimulation of CPV and, in particular, its relationship to the onset and severity of benign prostatic hyperplasia remain to be clarified.

Adolescent↗

A mutation in the first transmembrane domain of the lutropin receptor causes male precocious puberty.

We describe a patient with onset of puberty at the age of 5 yr. characterized by accelerated growth, enlargement of genitalia, pubarche, and serum hormone levels compatible with noncentral precocious puberty. Exon 11 of the LH receptor gene was amplified from genomic DNA by PCR and directly sequenced. We identified a heterozygous C to T base change at nucleotide position 1126, exchanging codon 373 from Ala to Val in the first transmembrane domain. The LH receptor sequence of the parents was normal. The mutated receptor displayed an up to 7.5-fold increase in basal cAMP production compared to that of the wild-type receptor in transiently transfected COS-7 cells. Treatment of the patient with ketoconazole resulted in inconsistent suppression of serum testosterone levels. At the age of 9.1 yr, central activation of the hypothalamic-pituitary-gonadal axis occurred. Additional treatment with a GnRH agonist led to complete suppression of testosterone secretion. This is the first description of constitutive activation of the LH receptor in the first transmembrane segment. It suggests the involvement of the first transmembrane helix in signal transduction and provides further insight into the structural organization of the seven transmembrane domains of the glycoprotein hormone receptor proteins.

Amino Acid Sequence↗

Long term outcome in adult males with classic congenital adrenal hyperplasia.

The effects of classic congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency on final height and fertility were evaluated in 30 affected males, aged 17-43 yr. The mean adult height of these patients was 165.64 +/- 8.4 cm (mean +/- SD), with a mean SD score of -1.65 +/- 1.2 cm. The difference between the mean final height SD score and mean target height SD score was -1.67 +/- 1.0 cm. All patients had short stature and did not reach their estimated target heights. There was no difference in height SD score between the salt-wasting and simple virilizing CAH patients. No correlation between the final height and degree of hormonal control or bone age advancement was observed. Of the 30 subjects, 18 had testicular sonograms. Abnormal sonogram findings of testicular adrenal rests were present in 9 patients (group 1), whereas sonogram without adrenal rests comprised the remaining 9 patients (group 2). In group 1, 8 of 9 patients and in group 2, 4 of 9 patients were salt-wasters; the remainder were simple virilizers. In group 1, 7 of 9 patients had semen analysis, and all were judged infertile. Of the 6 patients in group 2 who had semen analysis, 1 was azoospermic, and the remainder were normal. During optimal adrenal hormone suppression, gonadotropins at baseline and after GnRH stimulation were significantly higher in group 1 than in group 2, reflecting the loss of Leydig cell function to secrete testosterone. In conclusion, adult males affected with CAH due to 21-hydroxylase deficiency do not achieve the height predicted from parental heights. The presence of adrenal rests within the testes of adult males with classic CAH are more frequent in the salt-wasting form and are associated with a higher risk for infertility.

Adolescent↗

Postnatal development of the testes in the cuis, Galea Musteloides.

Testicular development to 9 months of age has been studied. Seminiferous tubule diameter increased in a linear manner between 13 and 65 days of age, and there was a steep increase in testicular weight with age. At about 9 months the animals weighed 400-500 g and total testicular weight was about 10 g. This relatively large testicular size was correlated with high sperm density in the semen. Spermatogenesis commenced at about 21-25 days of age, when the first spermatids were found. Spermatozoa appeared in a small proportion of seminiferous tubules by 31-35 days of age, and were seen in the epididymides of an animal of 31 and another of 34 days. Epididymal spermatozoas were consistently present in large numbers after 60 days and this correlated with the increased frequency of mature seminiferous tubules. Leydig cell size increased rapidly from 13 to about 60 days, then remained constant. Inferences have been drawn from this and the study of spermatogenesis about the level of testosterone secretion. The results indicate that the male cuis is almost fully grown and sexually mature by about 90 days of age.

Aging↗

Adrenocortical carcinoma responded to treatment with o,p'-DDD--a case report.

A case of a huge inoperable adrenocortical carcinoma which secreted testosterone without characteristic symptoms was treated with o,p'-DDD (2,2-bis(2-chlorophenyl-4 cholorophenyl) 1,1-dichloroethane). With this therapy, the tumor decreased in size which was confirmed by the computed tomography (CT). Eighteen months later, however, lethargy and logopathy appeared and the tumor grew again rapidly with the withdrawal of o,p'-DDD performed for the evaluation of these mental disturbances. The tumor then diminished gradually in size soon after the treatment was resumed and the above unfavorable symptoms were not developed again with the combined administration of a central nervous stimulant. During o,p'-DDD treatment, plasma testosterone and estrogen decreased, and plasma aldosterone also decreased but within the normal range. Plasma cortisol also tended to decrease despite hydrocortisone was administered. Plasma adrenocorticotropic hormone (ACTH) was maintained within the normal range for the first six months but then increased gradually. It decreased and became normal with the additional administration of hydrocortisone. The patient's normal menstruation at the preadministrative stage changed to oligomenorrhea, then amenorrhea after the treatment, but no endocrinological sign except for the menses was observed during the treatment.

Adrenal Cortex Neoplasms↗

Idiopathic male pseudohermaphroditism: variations in presentation and management.

UNLABELLED: Male pseudohermaphroditism (MPH) is the abnormal development of genitalia in an individual with a 46,XY chromosome complement and testicular tissue. The etiology of MPH is unknown in most cases, which are defined as idiopathic. OBJECTIVE: To analyze the data for cases of idiopathic MPH. PATIENTS AND METHODS: A retrospective study of 29 patients with idiopathic MPH and no uterus. RESULTS: Four patients had a family history of abnormal sexual development and five had low birth weight. The initial manifestations were sexual ambiguity (26), microphallus and hypospadias (2), and primary amenorrhea (1). Basal and/or stimulated testosterone concentrations showed insufficient testosterone secretion in three patients. Genitography showed a vagina in 13 patients. Male genitoplasties were performed on 21 out of the 24 patients reared as males and female genitoplasties on five patients. Histological studies of the gonads of these showed streak gonads in one, normal gonads in one and signs of testicular dysgenesis in three others. Molecular studies on the SRY gene (17) showed no mutation. CONCLUSIONS: Idiopathic male pseudohermaphroditism is a heterogeneous condition, even within families with a history of this condition. We propose a set of guidelines for the management of these patients.

Adolescent↗

Comparison of in-vitro bioactivity and immunoreactivity of serum LH in normal cyclic and hypogonadal women treated with low doses of LH-RH.

The in-vitro test of rat interstitial cell testosterone secretion and a radioimmunoassay (RIA) were used to explore the nature of the LH released in women in response to LH-RH. The ratio of in-vitro bioactivity to immunoreactivity (B:I) calculated for serum samples collected from hypogonadal women using the standard LER-907 for comparison was 13.25 +/- 0.56. This mean ratio was significantly elevated (P less than 0.02) above that found for normal cyclic women, 9.48 +/- 0.49. After one i.v. injection of 10 micrograms LH-RH, 5 hypogonadal and 6 luteal-phase women showed an initial significant drop in the B:I ratio (P less than 0.05 and P less than 0.02 respectively) followed by a steady significant rise (P less than 0.03; P less than 0.01 respectively). This drop in the B:I ratio as immunoreactive LH rose and the rise in the B:I ratio as immunoreactive LH fell may be the result of the release of two or more kinds of LH, one or more with a slower in-vivo clearance rate and an increased B:I ratio.

Female↗

The effects of treatment with melatonin on the ultrastructure of mouse Leydig cells: a quantitative study.

Both the presence of receptors for gonadal steroids in the pineal gland and in vitro observations of direct action of melatonin upon Leydig cells, inhibiting testosterone secretion, indicate a direct connection between pineal gland and gonadal function. In the present study, we used a transmission electron microscope to analyze the morphologic parameters of Leydig cells from adult Swiss outbred white mice treated with daily subcutaneous injections of 100 micrograms of melatonin (N-acetyl, 5-methoxytryptamine), during 22 consecutive days, compared with sham-control animals which had only received the melatonin vehicle. The melatonin group of mice showed a decrease in nuclear volume and fractional nuclear volume; smooth and rough endoplasmic reticulum; mitochondria; and Golgi complex. Our data also showed an increase in cytoplasmic volume, fractional cytoplasmic volume, and lysosomes in these same animals. The results suggest that melatonin, directly or indirectly, alters the ultrastructure of mouse Leydig cells and possibly influences their secretory activity by inhibiting their capacity to secrete steroids.

Analysis of Variance↗

Ontogeny of steroidogenic enzyme expression in the porcine conceptus.

This study examined fetal steroidogenic enzyme expression and function during pregnancy in the pig. Northern and Western analyses were performed to detect the cytochrome P450 enzyme 17 alpha-hydroxylase/17-20 lyase (P450c17) and that for cholesterol side-chain cleavage (P450scc), as well as 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) expression in several porcine fetal tissues. The data demonstrate higher steroidogenic enzyme expression in the fetal adrenal glands and testes than in the placenta at all stages of development examined. Although steroidogenic enzyme expression was maintained throughout gestation in both the fetal adrenals and the testes, adrenal P450c17 expression was higher in the early and late stages when compared with the intermediate stages of fetal development. The stimulation of fetal adrenal steroidogenic enzyme expression in the later stage fetuses was accompanied by increased expression of P450c17 in both the fetal testes and placenta. The expression of 3 beta-HSD by porcine fetal testes was low compared with that of the fetal adrenal gland at all stages of development. Adrenal explants and cultured cells secreted cortisol and androstenedione but much lower amounts of corticosterone, dehydroepiandrosterone and aldosterone. Secretion of cortisol and androstenedione by adrenal explants was maintained by ACTH for 5 days of culture but declined in controls. In cultured porcine fetal adrenal cells, ACTH and angiotensin II stimulated the secretion of multiple steroids. Porcine fetal testis explants and cultured cells secreted testosterone, dehydroepiandrosterone and androstenedione, but were only moderately responsive to trophic stimulation by LH. In general, the data suggest that the fetal adrenal glands and the fetal testes have the potential to contribute significantly to the production of steroids during pregnancy in pigs.

3-Hydroxysteroid Dehydrogenases↗

Influence of the gonad on the degree of suppression induced by an LHRH agonist implant in the marmoset monkey.

In a previous study pituitary-testicular function was shown to be maintained in a New World primate after the administration of an LHRH agonist implant. In the present study the mechanism of action of the same LHRH agonist (buserelin) on pituitary-gonadal function in the marmoset was investigated and a comparison made between the effects of treatment in three intact males, six adult cyclic females with regular ovulatory cycles, and six long-term ovariectomized animals. These were injected s.c. with an LHRH agonist implant (1.5 mg buserelin in a rod 0.5 cm long). In both the males and intact females, basal plasma LH concentrations were maintained within the normal range throughout the expected duration of agonist action (at least 3 months). Despite this, an absence of response to an LHRH challenge indicated that pituitary desensitization had occurred. In the intact females, ovulation was inhibited in five of six animals, plasma progesterone concentrations initially being maintained but subsequently remaining suppressed until 136 +/- 18 (S.E.M.) days after treatment. Responsiveness to administered LHRH returned prior to onset of return to ovarian cycles. In contrast, in ovariectomized marmosets, plasma LH was markedly suppressed to concentrations which were at or below the limit of detection of the assay and were therefore less than those observed in the buserelin-implanted intact animals. These results show that apparently normal pituitary-gonadal function in this species disguises an underlying pituitary desensitization to LHRH. This allows continuation of testosterone secretion in the male, but in the female ovulation is prevented, presumably as a result of failure of the desensitized pituitary to produce an LH surge.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Pituitary-testis function in rats treated neonatally with a gonadotrophin-releasing hormone agonist: short- and long-term effects.

Acute and long-term effects of neonatal and prepubertal treatments with an LH-releasing hormone agonist (LHRH-A) were studied in Wistar male rats. Animals injected with D-Ala6-D-Gly10-LHRH ethylamide (2 micrograms/kg per day) or vehicle from days 1 to 15 or from days 16 to 29 were killed at different ages. Treatment between days 1 and 15 induced a decrease in both pituitary FSH and LH content as well as a reduction in plasma FSH and blockade of the response to LHRH. These effects were apparent on day 16 after treatment. Basal and human chorionic gonadotrophin (hCG)-stimulated progesterone and testosterone secretion in vitro was similar in testes from male rats treated with LHRH-A or vehicle. Reduced testicular weight was observed until day 90, whereas puberty, spermatogenesis and fertility were unaffected. The decrease in plasma FSH concentrations after neonatal treatment with LHRH-A was also found in groups of animals killed on day 10 and was possibly the cause of reduced testicular weight, since treatment with FSH from day 1 to day 15 blocked the effect of LHRH-A. Likewise, treatment with LHRH-A from day 1 to day 15 also reduced FSH and LH secretion in males orchidectomized on day 1 of life. Animals injected with LHRH-A from day 15 to day 29 exhibited, at the end of the treatment period, reduced testicular weight, and decreased pituitary gonadotrophin content and plasma FSH concentrations, whereas LH plasma concentrations were normal. In adulthood, the pituitary-testis function did not vary from normal.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Differential effects of the administration of human chorionic gonadotropin to postnatal rats.

Neonatal and prepubertal male rats were treated with human chorionic gonadotropin (hCG, 5 IU/g body weight per day) on days 2-4 or 20-22. Depending on the date of treatment, different groups of rats were sacrificed at 5, 23, 30 and 100 days of age, in order to study the short- and long-term effects of the treatment with hCG on the development of the testes and sex accessory organs. Rats treated with hCG on days 2-4 showed increased number and size of foetal Leydig cells at 5 days of age. However, long-term effects include decreased numbers of adult-type Leydig cells, decreased weight of the testes and sex accessory organs, decreased basal and hCG-stimulated testosterone secretion, and delayed balano-preputial separation. In contrast, animals treated with hCG on days 20-22 showed similar short- and long-term effects, consisting of increased number of adult-type Leydig cells and macrophages, increased weight of the testes and sex accessory organs and advanced balano-preputial separation. In adulthood, both groups showed normal reproductive function. These results seem to indicate that the effects of hCG treatment in prepubertal rats are dependent on the type of Leydig cell stimulated, and suggest that foetal Leydig cells play a regulatory role in the early postnatal testicular development.

Animals↗

Collision tumor: serous adenocarcinoma and steroid cell tumor of the ovary.

A "collision" tumor between a serous papillary adenocarcinoma and a steroid cell tumor of the ovary is described. No similar combination has been reported in the literature. The steroid cell component secreted testosterone, resulted in considerable virilization of the patient, and appears to have preceded the carcinoma by several years. It remains problematical whether the androgenic milieu may have predisposed to the development of the second, malignant, tumor.

Aged↗

Age changes in rat testicular capsular and parenchymal delta 13-reductase and 15-hydroxyprostaglandin dehydrogenase activities.

Prostaglandin dehydrogenase (PGDH), delta 13-reductase, and total PGDH activities (the sum of the first two activities) were measured in rat testicular parenchymal and capsular preparations from 11 through 81 days of age. delta-13 Reductase activity closely paralleled PGDH activity and was substrate dependent except for the parenchymal activity at 61 and 81 days of age when something appeared to enhance its activity. All three activities, when expressed on a per milligram of tissue basis, were elevated at 11 days postpartum and then decreased to a low value at 21 days of age for the parenchyma and 21-32 days of age for the capsule. The elevated activity at 11 days of age suggested a possible elevation of enzyme activity by placental gonadotropins or possibly progesterone. Maximal, activity was observed at 51 days of age for the parenchyma and 61 days for the capsules with diminished activities observed with advancing age except for the parenchymal delta 13-reductase activity. On a per milligram of tissue basis, the capsule demonstrated more enzyme activity than did the parenchyma with maximal activities being observed at 51 days of age. Possible control mechanisms were the following: substrate induction, gonadotropins, testosterone, or those factors regulating testosterone secretion.

15-Oxoprostaglandin 13-Reductase↗

Flutamide blocks the self-priming effect of luteinizing hormone-releasing hormone in pubertal male rats.

Castration of pubertal or young adult male rats eliminates the self-priming effect of luteinizing hormone-releasing hormone on luteinizing hormone secretion. Testosterone, dihydrotestosterone, or estradiol will maintain this effect in castrated animals. In order to explore the mechanism by which both dihydrotestosterone and estradiol are capable of maintaining the effect, intact rats as well as castrated animals implanted with testosterone capsules were treated with the antiandrogen Flutamide. In both intact animals and castrated rats bearing testosterone-filled Silastic capsules, Flutamide blocked the self-priming effect. These data suggest that the androgen receptor is of primary importance in the maintenance of the self-priming effect.

Anilides↗