Successful fertilization and production of viable offspring in fish is determined by a number of factors. Important is the transfer of large numbers of highly motile, viable sperm to the female fish or to the eggs deposited into the water. The objectives of the present proposal are to investigate the structure and function proteins in fluids of a cartilaginous fish species which increase sperm motility and relax these fish's uterine smooth muscle. Specific goals are to: 1) Characterize the relaxation response of the fish uterine smooth muscle to the newly purified "raylaxin" molecule in male reproductive fluids and to isolate and characterize its receptor in the cell membrane of the uterine cells. 2) Identify and characterize the sperm stimulatory molecules in the fluids secreted over the fish sperm at the time of mating. Analytical chemistry techniques and microscopy will be used to achieve these goals. The results of these studies should have practical application in fisheries' management as well as contribute to the knowledge of basic biological mechanisms of reproduction.
