Commentary: standardization of nonsteroidal regulators of gonadotrophin secretion.

Abstract

The concept of nonsteroidal regulators of gonadotrophin secretion originated with the identification of inhibin – a hormone produced by the gonads that selectively inhibits the secretion of pituitary follicle stimulating hormone (FSH) – the existence of which was postulated some 70 years ago (Mottram and Cramer, 1923; McCullagh, 1932). However, the purification and characterization of inhibin was a long and arduous task confounded by many factors, including the wide range of starting materials, the different bioassay systems used to define and estimate inhibin activity, the properties of the protein that rendered it resistant to standard protein purification techniques, and the absence of a generally accepted reference preparation for inhibin activity (Findlay, 1986). In addition to being a member of a wider family of proteins with diverse biological activities in a number of systems, inhibin itself is a complex protein existing as different molecular mass forms as well as products of