These studies are to investigate how hormones from the brain of a primitive fish, the sea lamprey, control reproductive function. This hormone is a protein called gonadotropin-releasing hormone (GnRH). Gonadotropin-releasing hormone is present in all brains of all vertebrates. This hormone regulates reproduction by stimulating the release of hormones from the pituitary which, in turn, stimulate activity of the gonads. Since 1971, when the structure of mammalian GnRH was determined, over 5000 analogs have been made to GnRH and tested in hundreds of studies in mammals. Analogs are variants of the GnRH protein molecule with different substitutions of amino acids that can either make the GnRH a more potent hormone or an antagonist to the hormone. In mammals there has been great success using various mammalian GnRH analogs for sterilization, conception and other therapeutic uses. The scientists who are doing this study have identified the primary structure of GnRH in the sea lamprey and have provided evidence for its regulatory influence on the pituitary-gonadal axis. The goal of the present studies are to determine the biological effects of lamprey GnRH. The long-term goal of the studies is to develop lamprey GnRH analogs as an alternative method for sterilizing lampreys in a sterile-male release program in the Great Lakes region. This is an exciting possibility because these compounds are proteins which are easy to synthesize, easy to administer, easily degraded within the organism, and non-toxic to humans.
