The recent purification, sequencing and molecular cloning of inhibin have led to its redefinition incorporating reference to its structure in order to avoid confusion with other proteins with inhibin-like activity. Thus, inhibin is now defined as a glycoprotein hormone consisting of two dissimilar disulphide linked subunits termed α and β, which acts to inhibit the production and/or secretion of the gonadotrophins, preferentially that of FSH. The trophic action of FSH upon gonadal inhibin production has been confirmed in man and animals. On the other hand, the relative role of inhibin, the sex steroids and perhaps activin, in the physiological regulation of FSH remains unclear. The availability of inhibin radioimmunoassays and very recently, inhibin and activin produced by recombinant DNA technology (Mason et al., 1987), will allow such assessments and will clarify the physiological, pathological and potential therapeutic roles of inhibin. The unique ability of the inhibin subunits to form homo- or heterodimers with divergent biological activities and their homologies with other growth factors indicate that inhibin is a remarkable member of a family of proteins derived from a common ancestral gene. As such, the distinct possibility arises that proteins composed of inhibin α and β subunits will also show growth stimulatory or inhibitory activities. As presented above, tentative evidence exists for such function in respect of human gestation, adrenal cortical function, haemopoietic cellular differentiation and the paracrine regulation of ovarian function. The study of inhibin and related proteins seems certain to have ramifications far beyond the field of reproductive endocrinology.
|Number of pages||36|
|Publication status||Published - 1988|