Transgenic animals and gonadotrophins.

A variety of transgenic animal models has been developed to elucidate in vivo the functions of gonadotrophin genes. Some of these have focused on regulatory aspects through expression of gonadotrophin subunit promoter-driven reporter genes. Others have been carried out by overexpression or targeted disruption of specific gonadotrophin subunit genes, or by eliminating pituitary gonadotroph cells in transgenic mice by expressing toxic transgenes under gonadotrophin subunit promoters. In addition, the overexpression or knock-out of genes of other hormones (for example GH and the inhibin subunits) has elucidated the regulation of gonadotrophin gene expression. Many of the transgenic animals produced serve as good models for human diseases affecting the hypothalamic-pituitary-gonadal function. This review summarizes the key results obtained with these novel genome modification techniques on the physiology and pathophysiology of gonadotrophin synthesis and secretion.