The human granulosa cell model lessons gleaned from assisted reproductive technologies

The widespread availability of LGCs made possible by the use of ARTs has generated a plethora of information about . ovarian physiology and endocrinopathies. The detailed mechanisms by which gonadotropin binding stimulate granulosa cell proliferation and steroidogenesis are in the process of being elucidated, as are the mechanisms by which growth factors exert their paracrine effects. Many of these recent findings illustrate the diverse actions that hormones/growth factors can elicit in different physiological settings. For instance, the specific binding protein encountered by IGF or the combination of peptide subunits in the case of inhibin can dramatically affect the biological activity of these compounds. Furthermore, these investigations have demonstrated that granulosa cell function in vitro can be influenced by such diverse factors as the ovulation induction regimen administered, length of cell culture, cell density, and intrafollicular concentrations of hormones/growth factors. This review discusses the processes of differentiation, proliferation, and apoptosis in human granulosa cells derived through oocyte retrieval in preparation for ARTs. The activities of specific growth factors and detailed mechanisms of these events are discussed.