Bioassays of gonadotropins

Bioassays constitute a unique approach to determine the functional aspects of gonadotropins. Indeed, these highly complex glycoprotein hormones, inclu ding pituitary lutropin (LH) and follitropin (FSH), are heterogeneous in te rms of both peptidic and carbohydrate moieties, and, as a consequence, the bioactivity of the different molecular forms often does not match their imm unoreactivity. In this article, we review the different types of LH and FSH bioassays. conventional methods for measuring FSH bioactivity are first de scribed and include the in vivo Steelman and Pohley bioassay, the radioliga nd receptor assays (RRAs), the in vitro Sertoli cell bioassay, the in vitro granulosa cell bioassay, and the inhibin immunoassay. Recent methods based on cell lines transfected with cloned receptors, particularly the human FS H receptor, are then described. Methods for developing these assays are pre sented, and the advantages and disadvantages of the different bioassays are discussed. (C) 2000 Academic Press.