Immunoreactive relaxin was measured in plasma samples obtained from human volunteers utilizing the RIA procedure of Sherwood et al., as modified by O'Byrne and Steinetz for heterologous plasma samples. Immunoreactive hormone was not detected in samples obtained from men, and only rarely in plasma of nonpregnant women. Immunoreactive relaxin was present as early as the fourth week of pregnancy and was detectable throughout the course of gestation. Immunoreactive relaxin tended to be higher early in pregnancy, and there was no peak just before parturition as occurs in many other species. Our results are at variance with those of Bryant and coworkers, who reported high levels of immunoreactive relaxin in men and nonpregnant as well as pregnant women. The possible reasons for this discrepancy are presented.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.