This proposal will investigate how a substance (hormone) from the brain of a primitive fish, sea lamprey, controls reproductive functions. This substance from the brain is a protein called gonadotropin-releasing hormone. Gonadotropin-releasing hormone is present in all brains of all vertebrates including mammals (which includes humans), birds, reptiles, amphibians, and fish. Most studies on this brain substance have been done in mammals. More information is needed in other vertebrates. In mammals, many analogs (related compounds to gonadotropin-releasing hormone) have been made and used in research to test these proteins as conceptive and contraceptive measures. Some of these gonadotropin- releasing hormone analogs are presently being used in therapeutic clinical applications (breast cancer, prostatic cancer, etc.). Before these analogs could be made, numerous studies were (and are) necessary for the basic understanding on how these substances function. Dr. Sower's studies will focus on the basic understanding of how this gonadotropin releasing hormone works in a very primitive fish. Knowledge of the structure and function of this protein in vertebrates other than mammals will further our understanding of reproduction in vertebrates. In addition, these studies may lead to the development of gonadotropin- releasing hormone analogs which could be used for controlling reproduction in sea lampreys. One of the major goals of the Fisheries Commission is the development of a lamprey control program that will include not only the use of lamprey poisons in streams but also the development of contraceptive methods for reducing the numbers of sea lampreys in the Great Lakes Region. These investigations will include if gonadotropin-releasing hormone and analogs could be used to inhibit by sterilization or control reproduction in lampreys as a complementary method in maintaining numbers of lampreys in the Great Lakes.
