ABSTRACT
A synthetic nonapeptide, which is C-terminal sequence of 94-amino acid of prostatic inhibin peptide was tested for progesterone and estrogen secretion by mouse granulosa cell cultures. Nonapeptide suppressed the progesterone and estrogen synthesis, the magnitude of suppression was highest at 5 ng dose level for progesterone and 50 ng dose level for estradiol. The study suggests that, nonapeptide exerts its effect by impairing the binding of FSH to granulosa cell receptors.
Subject(s)
Animals , Cells, Cultured , Dose-Response Relationship, Drug , Female , Follicle Stimulating Hormone/metabolism , Gonadal Steroid Hormones/biosynthesis , Gonadotropins, Equine , Granulosa Cells/drug effects , Inhibins/pharmacology , Mice , Peptide Fragments , Progesterone/biosynthesisABSTRACT
Using specific polyclonal antibodies generated against a 13 Kd human testicular inhibin, immunocytochemical localization was carried out in epididymis of intact and castrated marmoset monkey and rat epididymis. Inhibin was found to be present in the cytoplasm of epithelial cells of caput, corpus and cauda epididymis. The intensity of staining and pattern of distribution did not change following castration. Further, the in vitro biosynthesis of inhibin studied by incorporating 3H-leucine and precipitating it with specific antibody indicated maximum biosynthesis in the corpus epididymis in case of marmosets and cauda in case of rats. Following castration in rats, the epididymal tissue still retained the capacity to biosynthesize inhibin. These studies indicate that marmoset and rat epididymis are capable of biosynthesizing/absorbing inhibin and whose synthesis does not depend on androgens.
Subject(s)
Animals , Callithrix , Epididymis/metabolism , Immunohistochemistry , Inhibins/analysis , Male , RatsABSTRACT
Effects of prostatic inhibin peptide and its synthetic fragments on FSH biosynthesis by the human pituitary and prostate, were examined in vitro. The results showed that FSH biosynthesis by prostatic tissue is modulated by these peptides in a similar fashion to that observed at the pituitary level.
Subject(s)
Amino Acid Sequence , Animals , Follicle Stimulating Hormone/biosynthesis , Humans , Male , Molecular Sequence Data , Peptide Fragments , Peptides/metabolism , Pituitary Gland/metabolism , Prostate/metabolism , Prostatic Secretory Proteins , RatsABSTRACT
Evidence to demonstrate suppressive effect of inhibin on prolactin has been presented. The inhibin preparations derived from human testicular tissue, human seminal plasma and porcine follicular fluid were tested and all the three preparations were found to exhibit prolactin suppressing activity.
Subject(s)
Animals , Follicle Stimulating Hormone/antagonists & inhibitors , Humans , Inhibins/pharmacology , Luteinizing Hormone/antagonists & inhibitors , Male , Pituitary Gland/drug effects , Prolactin/antagonists & inhibitors , RatsABSTRACT
Synthesis and biological profile of a decapeptide analogue, [Tyr85, Cys(Acm)87]85-94 of human seminal plasma inhibin (HSPI) are described. The peptide suppressed the circulatory levels of follicle stimulating hormone (FSH) in adult male rats. No change in the levels of luteinizing hormone (LH) and prolactin (Prl) was observed. Whereas the peptide suppressed the release of both FSH and LH in vitro. This decapeptide is the smallest peptide reported so far to have FSH suppressing activity.