title: Feedback regulation by inhibins A and B of the pituitary secretion of follicle-stimulating hormone.
abstract: Inhibins A and B are gonadal factors that negatively regulate FSH synthesis by the anterior pituitary. Across the menstrual cycle, women show a strong inverse correlation between circulating FSH and inhibin B, estradiol, and anti-Mullerian hormone (AMH), but not with inhibin A. Estradiol is believed to provide a tonic inhibitory effect while the inhibitory role of AMH is unknown. In human males, inhibin B is the primary testicular factor regulating FSH with limited effects by gonadal steroids. In vitro and in vivo studies in rats indicate that inhibin B is more biologically active than inhibin A but showed a lower affinity for the activin type II receptors and the co-receptor, betaglycan, suggesting an alternative mechanism. While this review reinforces the important role inhibin plays in regulating FSH, the observed differences in mode of action of inhibins A and B and their interplay with other gonadal factors are still poorly understood.
authors.affiliation: Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia.
authors.forename: Yogeshwar
authors.initials: Y
authors.lastname: Makanji
authors.forename: Craig A
authors.initials: CA
authors.lastname: Harrison
authors.forename: David M
authors.initials: DM
authors.lastname: Robertson
mesh_terms: D000818:Animals; D025461:Feedback, Physiological; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D006801:Humans; D007265:Inhibins / Q000502:physiology*; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism*
chemical_list: C422362:inhibin A; C422364:inhibin B; D007265:Inhibins; D005640:Follicle Stimulating Hormone