title: The synthesis and secretion of inhibins.
abstract: Inhibin A and B, dimeric glycoproteins comprising an α- and β((A/B))-subunit, negatively regulate follicle stimulating hormone (FSH) synthesis by the pituitary. The expression of α- and β-subunits within Sertoli cells of the testis and granulosa cells of the ovary is controlled by a range of transcription factors, including CREB, SP-1, Smads, and GATA factors. The inhibin α- and β-subunits are synthesized as precursor molecules consisting of an N-terminal propeptide and a C-terminal mature domain. Recently, we showed that hydrophobic residues within the propeptides of the α- and β-subunits interact noncovalently with their mature domains, maintaining the molecules in a conformation competent for dimerization. Dimeric precursors are cleaved by proprotein convertases and mature inhibins are secreted from the cell noncovalently associated with their propeptides. Propeptides may increase the half-life of inhibin A and B in circulation, but they are readily displaced in the presence of the high-affinity receptors, betaglycan, and ActRII.
authors.affiliation: Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia.
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Walton
authors.forename: Yogeshwar
authors.initials: Y
authors.lastname: Makanji
authors.forename: David M
authors.initials: DM
authors.lastname: Robertson
authors.forename: Craig A
authors.initials: CA
authors.lastname: Harrison
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation; D006801:Humans; D007265:Inhibins / Q000235:genetics / Q000378:metabolism*
chemical_list: D007265:Inhibins