The role of extracellular loop three of the human gonadotropin releasing hormone receptor in ligand selectivity

Bibliography: leaves 123-146. ; The hypothalamic neuropeptide, gonadotropin releasing hormone (GnRH) perferentially inteacts with GnRH type I receptors on the gonadotropes in the anterior pituitary. Activation of the GnRH receptor is required for the biosynthesis and release of luteinizing hormone (LH) and follicle stimulating hormone (FSH), which regulate reproductive function. Multiple forms of GnRH are present in most vertebrate species and are thought to have physiological functions in addition to regulating pituitary hormone release. The mammalian type I GnRH receptor is proposed to discriminate between endogenous forms of GnRH (King and Millar, 1995). In this thesis the mechanism of the GnRH selectivity by a mammalian type I GnRH receptor is examined at molecular level and previous hypotheses are re-evaluated.