Search PubMed⌕ Search

Biomedical subjects

A R Sheth

Publications and source records attributed to A R Sheth.

At least 91 records · Page 5Linked to original sources
PubMed1985

Immunoreactive inhibin-like material in serum and gastric juice of patients with benign and malignant diseases of the stomach.

Immunoreactive inhibin-like material (ILM) was measured by radioimmunoassay (RIA) in serum and gastric juice samples of 23 fasting normal men, 27 men with chronic superficial gastritis (CSG), and 21 men with carcinoma of stomach (5 for gastric analysis). Serum ILM levels in carcinoma of stomach patients (367 +/- 55.5 ng ml-1) were significantly higher than in normal men (15.4 +/- 2.6 ng ml-1; P less than 0.01) and in patients with CSG (109.8 +/- 17.7 ng ml-1; P less than 0.05). Sixty two per cent and 86% of patients with carcinoma of stomach showed elevated ILM levels which were higher than the highest noted in patients with CSG and normal men respectively.

Adult↗
PubMed1985

In vivo and in vitro actions of low-molecular-weight gonadal peptides.

Two low-molecular-weight gonadal peptides, IRRP3 and IRRP5, have been isolated from sheep ovaries having different biological properties in male rats. The peptide IRRP3 has specific effect on FSH secretion as well as release at the pituitary level, in vitro binding of labeled FSH to testicular receptor, and in vivo uptake of labeled FSH by the testis, whereas peptide IRRP5 has specific effect on LH secretion at the pituitary level, in vitro binding of labeled LH to testicular receptor, and in vivo uptake of labeled LH by the testis.

Animals↗
PubMed1985

Cellular immunolocalization of inhibin-like peptide in human benign prostatic hyperplasia.

Immunoperoxidase staining method and specific antisera against highly purified inhibin-like material (ILM) from human seminal plasma were utilized to localize immunoreactive ILM in benign hyperplastic prostate (BPH) in human. Immunoreactive ILM was strictly localized to glands of hyperplastic nodules. The concentration of ILM was more in epithelial cells lining the healthy lobule than in those undergoing atrophy.

Aged↗
PubMed1985

Endocrine control of inhibin biosynthesis by human placenta.

In vitro synthesis of inhibin-like activity was localized in the fetal part of the human placenta. Of the various hormones, hCG stimulated inhibin synthesis while progesterone, estradiol, LHRH and prostaglandin inhibited the synthesis. Prolactin did not significantly alter the inhibin synthesis.

Chorionic Gonadotropin↗
PubMed1984

Complete amino acid sequence of human seminal plasma beta-inhibin. Prediction of post Gln-Arg cleavage as a maturation site.

The complete sequence of a 94 amino acid human seminal plasma polypeptide exhibiting inhibin-like activity is presented. This molecule, called beta-inhibin, selectively and specifically suppresses the release of pituitary FSH in vivo as well as in vitro. It does not affect the secretion of LH. Such a novel acidic protein contains a very basic C-terminal segment which is easily cleaved by mild tryptic digestion. It is predicted that the FSH inhibiting activity may reside within this region of the molecule. This would imply a post Gln-Arg cleavage to release the basic C-terminal active moiety.

Amino Acid Sequence↗
PubMed1984

Characterization of a polypeptide from human seminal plasma with inhibin (inhibition of FSH secretion)-like activity.

A polypeptide in preparations of 'large' form (Mr approximately 14000) material with inhibin-like activity (inhibiting FSH secretion) has been isolated from human seminal plasma. Its amino acid composition, cleavage pattern with CNBr, N-terminal sequence, and properties on reverse-phase high-performance liquid chromatography establish this inhibin-like preparation to be homogeneous. The polypeptide contains close to 130 residues, has a free N-terminal serine residue, a methionine residue in position 19, and a dibasic structure (Arg-Lys) in positions 16-17.

Amino Acid Sequence↗
PubMed1984

Local anti-fertility effect of inhibin-enriched preparation (IEP) in female hamsters.

An inhibin-enriched preparation (IEP) involved in the regulation of follicle stimulating hormone (FSH) is known to play an important role in the normal ovarian cycle. In utero administration of 10 micrograms of IEP on day 3 of pregnancy completely prevented implantation in hamsters. No toxic effect of IEP was observed on the blastocysts as indicated by the dye exclusion test performed with Trypan blue. Thus, the results of the present study indicate an extra-pituitary site of action for the anti-implantation effect of IEP.

Animals↗
PubMed1984

Role of the prostate in the regulation of pituitary secretion of follicle stimulating hormone.

The secretion of Follicle Stimulating Hormone by the pituitary gland is not regulated entirely by the negative feedback from gonadal steroids. There is ample evidence that the secretion of FSH is regulated by a non-steroidal hormone of gonadal origin termed "inhibin". Using a radioimmunoassay procedure, immunoreactive inhibin-like material was quantified in tissue and biological fluids to study its role in reproductive pathophysiology. High levels of immunoreactive inhibin were observed in human prostate as compared to testis. Biologically active as well as immunoreactive inhibin-like material (ILM) was obtained from human prostate, and was similar to that obtained from human seminal plasma under identical conditions. In patients with benign prostatic hypertrophy, high inhibin levels were observed which reduced after prostatectomy. The presence of immunoreactive inhibin in urine as well as semen of vasectomized and gonadectomized subjects indicates that prostate also secretes inhibin-like material. The specific receptors for inhibin as well as biosynthesis of inhibin in human prostate have been reported. Elevation of serum FSH levels following castration of adult male rats was further enhanced in animals where castration as well as prostatectomy was carried out. All these results demonstrate that apart from the testis, the prostate also secretes ILM and further suggest that the prostate along with testis, may play an important role in the regulation of pituitary secretion of FSH.

Animals↗
PubMed1984

Evidence for the prostatic origin of immunoreactive inhibin-like material in human seminal plasma.

Inhibin is defined as a gonadal peptide exerting an inhibitory effect on the secretion of follicle-stimulating hormone (FSH) by the pituitary. Using a radioimmunoassay (RIA) procedure developed for a homogeneous inhibin-like peptide with a molecular weight of 14 000 daltons isolated from human seminal plasma, immunoreactive inhibin-like matrial (ILM) was quantitated in serum, urine and semen of men in order to investigate its origin. Vasectomy did not result in a significant reduction in seminal plasma ILM. Determination of ILM immunoreactivity in ejaculates form normal men and semen samples characterized by prostate-rich and prostate-deficient secretions, indicated high levels of ILM in the prostatic secretions. Immunoreactive ILM levels estimated in different fractions of split ejaculates from normal men paralleled those of zinc and acid phosphatase activity and were significantly higher in fractions representing prostatic secretions compared to those representing the secretions of seminal vesicles. Estimation of ILM in semen, serum and urine from bilaterally gonadectomized men showed that immunoreactive ILM levels remained high after gonadectomy. It is concluded that the bulk of the immunoreactive ILM present in the semen, blood and urine of men is not secreted by the testes. The principal site of origin of this material, at least in semen, appears to be the prostate.

Acid Phosphatase↗
PubMed1984

Studies on inhibin-like peptide in gastric juice and serum of patients with duodenal ulcers.

Immunoreactive inhibin-like material (ILM) was measured by radioimmunoassay in serum and gastric juice samples of 23 fasting normal men and 23 men with duodenal ulcers (DU). Concentrations of ILM in gastric juice and serum of patients with DU were significantly higher than those in normal men (P less than 0.01). A strong positive correlation (r = 0.894) was observed between pH and ILM levels in gastric juice of normal men but not in patients with DU. Inhibin-like material in the gastric juice had a chromatographic profile similar to that of human seminal plasma.

Adult↗
PubMed1984

Serum inhibin levels after administration of hCG.

Administration of hCG to normal healthy men caused 40 fold increase in circulating levels of inhibin at 24 hr. FSH levels decreased between 72-120 hr of hCG injection. Although, testosterone levels were maintained at higher levels during hCG therapy for more than 10 days, inhibin and FSH levels returned back to pretreatment levels, indicating involvement of hCG in the regulation of circulating levels of inhibin.

Adult↗
PubMed1984

Circulating levels of inhibin in cancer.

Study on frequency distribution of serum inhibin levels--a peptide hormone involved in suppression of follicle stimulating hormone--was carried out using a specific radioimmunoassay developed in this laboratory, on 237 sera from normal men and women, from male and female patients with cancer prostate, lung, stomach and breast, and from patients with non-malignant disease of the respective organ. The mean serum inhibin levels in patients with malignant and non-malignant disease of prostate (90 +/- 19 ng/ml and 54 +/- 8 ng/ml) were significantly higher than found in normal men (31 +/- 9 ng/ml). However, the levels in cancer of stomach (70 +/- 9 ng/ml) and lung (45 +/- ng/ml) were higher than those in normal as well as benign condition of stomach and lung. The mean serum inhibin in case of women with cancer of breast (27 +/- 5 ng/ml) and lung (53 +/- 16 ng/ml) were significantly higher than those found in normal women (15 +/- 2 ng/ml) and in women with benign disease of breast (10 +/- 3 ng/ml) and lung (21 +/- 4 ng/ml). Considering the levels in individual patient basis, 66% of the patients with cancer of stomach had higher inhibin concentration than the uppermost limit of inhibin found in normal men and in contrast none in benign disease of stomach.

Aged↗