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Biomedical subjects

A R Sheth

Publications and source records attributed to A R Sheth.

312 records · Page 18Linked to original sources
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Hormonal modulation of invitro biosynthesis of inhibin like peptide by human prostate.

The hormonal regulation of inhibin biosynthesis by human benign hyperplastic prostate tissue was studied by determining the incorporation of 3H-leucine. 3H-inhibin, synthesized de novo, was immunoprecipitated from the culture media using specific antibodies to human prostatic inhibin. Testosterone and estradiol had no effect on inhibin biosynthesis whereas hFSH and PMSG had stimulatory effect. A decrease in inhibin biosynthesis was noticed on the addition of LHRH, TRH, hCG, hLH and human prolactin.

Chorionic Gonadotropin↗
PubMedDate not supplied

Role of inhibin in polycystic ovarian syndrome.

The possible role of inhibin in the etiology of polycystic ovarian syndrome (PCO) was studied. In rats PCO was induced by thiouracil and human chorionic gonadotropin (hCG). These animals were grouped under different treatment schedules: inhibin; antibodies to inhibin; ovine follicle stimulating hormone (FSH). In rats treated with antibodies to inhibin, there was a decrease in ovarian weight concomitant with specific increase in serum FSH levels. No changes in serum luteinizing hormone (LH) and prolactin levels were observed. However, testosterone levels were significantly decreased. Histological examination of the ovaries showed a marked arrest in the cyst formation with new growing follicles. In animals treated with inhibin, testosterone levels increased without any accompanying changes in ovarian weight. The circulating levels of prolactin and LH were unaffected. A decrease in serum FSH levels was accompanied by an increase in the number of cysts. The study corroborates the hypothesis that inhibin is involved in the development of PCO syndrome. Hence, an antagonist to inhibin may prove useful for the treatment of women with this condition.

Animals↗
PubMedDate not supplied

Reversal of the anti-implantation effect of inhibin with progesterone in the hamster.

Inhibin, the gonadal peptide involved in regulation of follicle-stimulating hormone (FSH), exhibited anti-implantation activity in intact and ovariectomized pregnant hamsters. Administration of progesterone reversed the anti-implantation activity of inhibin. Studies were carried out to determine the effect of inhibin on the in vitro synthesis and release of progesterone by the corpora lutea of pregnant hamsters. Inhibin (10 micrograms) was observed to decrease progesterone release by 28%. The administration of exogenous progesterone (2 mg/day) was observed to overcome the anti-implantation effect of inhibin in ovariectomized, pregnant hamsters. These results indicate a possible action of inhibin to interfere with progesterone at the ovarian and/or uterine level in order to exhibit the anti-implantation activity in the hamster.

Animals↗
PubMedDate not supplied

The role of adrenal and pineal glands on the hypothalamo-pituitary axis in adult male rats.

Although there have been reports on the effects of adrenal and pineal gland secretions on the hypothalamus and the pituitary, the maintenance of rhythmicity by these glands has not been reported so far. The present data deals with the alterations in the periodicity of hypothalamo-pituitary axis after the surgical removal of either adrenal, gonad or pineal in adult male rats. The data indicated an alteration in the 24 hour pattern of hypothalamic content of LHRH after adrenalectomy, castration or pinealectomy. In adrenalectomy group, the in vitro responsiveness of pituitary decreased at 0600 h and 100 h as compared to the intact rats, resulting in a low amplitude of LH circadian rhythm. The pituitaries of pinealectomized rats showed increased sensitivity at 1000 h and 1800 h which resulted in two peak LH concentration at those time intervals. Further, pinealectomized rats showed a selective five fold increase over 24 hr in serum FSH concentration as compared to intact rats suggesting dissociation in the release of FSH and LH.

Adrenal Glands↗
PubMedDate not supplied

Occurrence of FSH, inhibin and other hypothalamic-pituitary-intestinal hormones in normal fertility, subfertility, and tumors of human testes.

OBJECTIVE: To compare the distribution of peptide hormones in presumably normal human testicular tissues and specimens exhibiting any of five pathologies. METHODS: Biopsies from patients having testicular malfunctions were prepared as sections and specifically immunohistochemically stained for inhibin, FSH, serotonin, AUP, and oxytocin. RESULTS: Immunocytochemical studies revealed the presence of various hypophysial-pituitary-intestinal hormones, viz., FSH, inhibin, arginine vasopressin (AVP), calcitonin, serotonin, oxytocin, adrenocorticotropin (ACTH), gastrin, secretin, and somatostatin in human testicular biopsies exhibiting normal spermatogenesis, Sertoli-cell-only syndrome, spermatogenic arrest, Leydig cell hyperplasia, Leydig cell tumor, and seminoma. Intensity of immunostaining for all peptides except FSH was stronger in cases of subfertile as compared to normal testis. Intensity of immunostaining with inhibin was maximum in Leydig cell tumor. CONCLUSION: These regulatory peptides may be involved in the pathophysiology of the testes.

Arginine Vasopressin↗