Complementary deoxyribonucleii acid (Cdna) cloning and dna sequence analysis of rat ovarian inhibins

Abstract

Two forms of inhibin (A and B), gonadal polypeptide hormones that selectively suppress the secretion of FSH from the anterior pituitary, have been characterized from the porcine and human species, each being composed of a common α-chain and one of two distinct, but homologous β-chains, i.e. αβA and αβB- Using cDNAs encoding the porcine inhibin subunits we have cloned and sequenced the cDNAs encoding the α, βA, and βB chains of rat ovarian inhibin. Northern analyses of rat testicular RNA with rat ovarian cDNA probes show the presence of mRNAs encoding α and βB chains, but no detectable mRNA encoding the βA chain under our experimental conditions. This suggests that there may be specific and distinct physiological roles for inhibins A and B. In addition, if there is no extratesticular source of βA mRNA, then the male rat may be devoid of the stimulators of the secretion of FSH, i.e. activin (βAβB) and homoactivin A (βAβA), which are derived from the β subunits of the two inhibins. (Molecular Endocrinology 1: 388-396, 1987). © 1987 by The Endocrine Society.