Biomedical subjects
Publications and source records attributed to A R Sheth.
The effect of physiological doses O-prolactin (0-10 ng) and spermine (0-2 mg) on the intracellular content of zinc of human spermatozoa was studied. The results revealed the negative correlation of the zinc content with prolactin or spermine concentration.
Effects of the administration of PGs A-1, E-2 and F-2 alpha (150 micrograms/rat b.i.d. for 10 days) were studied. Significant increase in testicular weight was observed only in PGE-2 treated group. Testicular ascorbic acid content reduced significantly by treatment with all the PGs. PGE-2 treatment caused a significant decrease in the content of testicular cholesterol, while no change was observed in the same and prostatic acid phosphatase activity in any of the PG treated groups. Blood plasma levels of testosterone drastically reduced by both PGE-2 and PGF-2 alpha, while there was no change in the levels of plasma LH in any of the groups. Plasma FSH levels increased significantly in PGA-1 treated rats only. The results suggest that 1) There is a direct action of PG particularly PGE-2 on testicular weight. PGE-2 increases testicular weight possibly by preventing degeneration of spermatids, 2) PGE-2 acting directly on the testis, reduces testicular ascorbic acid content, stimulates the conversion of cholesterol to pregnenolone but depresses the conversion of the latter to testosterone.
Progressive Motility Sustaining Factor (PMSF) was isolated from human epididymides. PMSF could significantly improve progressive motility of oligozoospermic as well as asthenozoospermic semen. PMSF was found to increase cyclic AMP accumulation by the human spermatozoa indicating its possible mode of action.
Levels of inhibin in the spermatocyte and spermatid enriched fractions of rat testicular extract were estimated using a specific and sensitive radioimmunoassay. The fraction enriched in spermatids had the highest amounts of inhibin activity. The results of the study indicate that the spermatids may be likely source of inhibin.
Cowper's glands of rats were analysed for ten different biochemical parameters including enzymes and substrates under different hormonal status of the animals. Sialic acid, glycogen and activities of maltase and alkaline phosphatase enzymes of the prepuberal glands were found to be elevated to the levels of the adult (control animals) after treatment with testosterone propionate. On the other hand, following castration of adult animals a dramatic fall of the maltase activity of the gland was recorded; other parameters studied also registered a significant fall from their normal values. However, following treatment with testosterone propionate of the castrate animals all parameters excepting total lipids and phospholipids were found to recover. Sialic acid of the prepuberal animals and maltase activity of the adult were highly sensitive to testosterone propionate.
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Gossypol acetic acid was given to male rats at a dose of 7.5 mg/rat/day six days a week for ten weeks. After nine weeks of gossypol treatment no implantation sites were observed in the females mated with gossypol treated males. After ten weeks of gossypol treatment all the spermatozoa in the vas deferens were non-motile. Gossypol treatment did not affect the body weight and the weights of the accessory sex organs. Plasma LH and FSH levels, hCG binding in testis and succinic dehydrogenase (SDH) and adenosine triphosphatase (ATPase) activities in liver, kidney and testis were not affected by gossypol treatment. Histological observations of the testis revealed partial damage to the seminiferous tubules. Single high doses of gossypol did not induce significant changes in the body weight and weights of testis and accessory sex organs. ATPase activity in the testis was reduced significantly after gossypol treatment, the enzyme activity in liver and kidney, was however, affected at high doses only. Gossypol treatment had no effect on the histoarchitecture of the testis. Intratesticular administration of gossypol evoked localized damage in the testis. Gossypol treatment had no effect on I125 FSH binding to the rat testis homogenate in vitro.
The effect of a single administration of testosterone oenanthate (250 mg, intra-muscularly) on serum and seminal plasma inhibin concentrations were studied in four adult human volunteers. A significant decrease in serum FSH and LH levels were observed by day 6 when the serum testosterone levels were high. These were followed by a sharp increase in serum and seminal plasma inhibin concentration by day 8 and day 12 respectively. The present investigations also suggest the existence of a positive relationship between the serum and seminal plasma inhibin concentrations.
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Serum inhibin, LH and FSH were measured in infertile married men. A negative correlation between FSH/LH ratio and serum inhibin levels was observed. Comparison of serum inhibin and FSH levels with testicular histology indicated an association between the formation of spermatids and the elevation of inhibin levels. A plot of serum inhibin levels versus testicular inhibin levels (ng/100 mg protein) showed an excellent correlation.
Gossypol acetic acid (4 mg/day/5 days a week) suspended in Tonoferon tonic was given to male bonnet monkeys, Macaca radiata, by oral route for 3 months. Marked reduction in the sperm count/ejaculate and sperm motility were observed after gossypol treatment; both motility and sperm count/ejaculate returned to the normal level 8-10 weeks after termination of gossypol treatment. The citric acid and fructose levels in the semen of gossypol treated monkeys were not different from those of the controls.
Distribution of immunoreactive inhibin material (IR-ILM) in different regions of human prostate was studied by using specific radio-immunoassay. Mean IR-ILM concentrations in the central, peripheral and periurethral zones were 27.3 +/- 9.3, 2.4 +/- 0.7 and 3.0 +/- 1.5 micrograms/mg protein respectively (P central vs periurethral and peripheral less than 0.05).
A method involving thin layer chromatography (TLC) was developed to assess 5 alpha-DHT-reductase activity in rat ventral prostate, in terms of the amount of testosterone metabolised to its main 5 alpha-reduced compound, dihydrotestosterone (DHT). Using this method an in vitro study was carried out to determine 5 alpha-DHT reductase activity in the rat ventral prostate as modulated by thyroid releasing hormone (TRH). The study revealed a decrease in the enzyme activity with increasing doses of TRH, as shown by a decrease in the extent of reduction of testosterone to DHT. The ratios of the counts for DHT and testosterone however did not show any dose related effect.
A study was undertaken to see the effects of antiserum to human seminal plasma inhibin (hSPI) on the morphology of rat testis. Morphometric, light microscopic, and ultrastructural studies were done on rat testis after 4, 8, and 12 weeks of administration of antiserum to hSPI. Daily sperm production rate was also estimated by histometric method. The light microscopic analysis showed a slight decrease in tubular diameter which was not significant. The degenerative changes in the tubules were marked after 12 weeks of treatment. The daily sperm production rate was reduced by 50% after 12 weeks of treatment. The ultrastructural study revealed phagocytosis of elongated spermatids and spermatozoa enclosed in a vacuole surrounded by Sertoli cells. The Sertoli cells were dedifferentiated into an immature type. The spermatogonia were not affected. The treatment with antiserum to hSPI alters testicular morphology at the spermatid and mature spermatozoa level. Since treatment with AshSPI is known to elevate the FSH level it appears that the morphological changes correlate with the endocrine status.
Historically, inhibin was thought to be a testicular hormone involved in the regulation of pituitary FSH by a negative feedback control. The ability of inhibin to preferentially suppress FSH without affecting LH triggered extensive research for its possible use as a male contraceptive, suggesting a plurality of molecular forms and a multiplicity of biological actions of this putative hormone. It also became evident that inhibin is not unique to the testis, as presumed earlier, and can even be obtained from the ovary. This has necessitated a fundamental revision of the original concept of inhibin. Unfortunately, not many perceive inhibin as a loose conglomerate of structurally dissimilar, FSH-suppressing proteins and insist on singling out a 32-kDa protein derived from ovarian follicular fluid to be designated as inhibin. This article highlights features common to two distinctly different types of inhibin: seminal inhibin and ovarian inhibin. Evidence is also provided to indicate that the term inhibin need not be specific to the ovarian protein, but encompasses proteins hitherto dismissed as inhibin-like or inhibin-related proteins.
Immunocytochemical localization of neuropeptides (beta-endorphin, substance P, arginine vasopressin, oxytocin), pituitary hormones (adrenocorticotropin, prolactin, growth hormone, follicle stimulating hormone (FSH), gonadal inhibin, gastrin, and human chorionic gonadotrophin (hCG)) was carried out in marmoset testis during development. Both intensity of immunostaining and distribution of these peptides in testicular compartments viz. seminiferous tubules and Leydig cells changed dramatically during development. In vitro biosynthesis of inhibin and FSH was increased by hCG, whereas prolactin (5 micrograms) and prostatic inhibin peptide suppressed the synthesis of these hormones.
Semen samples (n = 40) obtained from males attending an infertility clinic were subjected to bacteriological culture and categorized as bacteriologically negative (group I) and bacteriologically positive (group II) depending on the culture positivity. Semen samples from both groups were simultaneously analyzed for routine parameters such as volume, count, motility, viability, morphology, pH, and hypoosmotic swelling. Seminal plasma was assayed for levels of prolactin (PRL), prolactin-suppressing factor (PSF), prostatic inhibin peptide (PIP) and zinc (Zn). Patients in group II (n = 25) showed statistically significant alteration (p < .01) in semen parameters such as motility, percent normal morphological forms, and percent normal HOS test as compared to group I (n = 15). There was a negligible change in the sperm concentration between the two groups. The semen volume, viability, and pH did not show any variation. Among the regulatory factors assayed, there was a significant change in the Zn, PSF (p < .05), and PIP (p = .01), while no such alterations were seen for PRL. The results suggest that bacterial infection affects fertility either by affecting the seminal characteristics directly or by acting on the regulatory systems.
Polyclonal antibodies to intact inhibin (94 amino acids, R-94, 10.5 kDa) and its sequence specific synthetic fragments (R-9, R-17) were evaluated for their effect on various physical and biochemical parameters of sperm function. Intact inhibit had maximum deleterious effect on quantitative motility and mean forward progression of spermatozoa. Antibodies had no effect on sperm fructolysis and sperm nuclear chromatin decondensation reaction. Sperm plasma membrane was damaged in antibodies treated spermatozoa as evidenced by hypoosmotic swelling test and sperm lipid peroxidation reaction.