REGULATION OF GONADOTROPIN-RELEASING-HORMONE (GNRH) GENE-EXPRESSION IN HYPOTHALAMIC NEURONAL CELLS

1. Gonadotropin-releasing hormone (GnRH) is the hypothalamic releasing factor that controls pituitary gonadotropin subunit gene expression a nd indirectly gametogenesis and steroidogenesis from the gonad, which results in reproductive competence. 2. GnRH is synthesized in only abo ut 1000 neurons in the hypothalamus and released in an episodic fashio n down the median eminence to regulate gonadotropin biosynthesis. 3. A lthough much is known about the secretory dynamics of GnRH release, li ttle is known about the pretranslational control of GnRH biosynthesis due to lack of appropriate model systems. The recent availability of i mmortalized neuronal cell lines that produce GnRH allows investigators for the first time to begin to dissect the factors that directly regu late GnRH gene expression. 4. This article reviews the current state o f knowledge concerning the mechanisms that direct tissue-specific and peptide hormone control of GnRH biosynthesis.