This proposal describes and experimental approach to study the role of the hormone relaxin in gestation and partuirition, with particular emphasis on the study of nonovarian sources of relaxin. Specific projects include: 1) isolate and characterize relaxin from the woman and ewe; 2) determine the organ and celluar source of relaxin in these species; 3) investigate the ewe as a model system in which to study relaxin production and secretion.