In this application, SH will be isolated from the neurohormone, shedding-substance (SS), by HPLC, and if successful, its chemical structure will be determined. Location(s) of SH (in addition to the radial nerve) will be determined using extracts of various organs. The hypothesis that it is the withdrawal of SH that allows the ever present SS to then initiate the release of gametes will be tested. To ascertain if SH is a "hormone", the presence of SH in the circulating fluids of pre- and post-shed animals will be examined. To more precisely locate and observe secretory activity of both SH and SS, different colored fluorescent antibodies will be made. The role of SH will be further elucidated after determining if egg (or sperm) release is inhibited after in vitro injection and/or implantation of SH into naturally spawning starfish.