Immunofluorescence studies on the localization of relaxin in the corpus luteum of the pregnant rat

We have used 17 day pregnant Long-Evans rats to demonstrate, utilizing indirect fluorescent antibody methods, that relaxin is present in luteal cells of the ovary. Furthermore, this technique revealed that the highest concentration of relaxin is localized in the juxtanuclear area of the cell, presumably over the Golgi region. The role of granular cells of the uterine metrial gland as a source of rela.xin in the pregnant rat is still not clarified. Using the indirect fluorescent antibody technique only one experiment out of six demonstrated the presence of relaxin in the granular cells of the metrial gland, However, other investigators claim to have localized relaxin in these granular cells by the fluorescent antibody technique. Failure to obtain such consistent results in our studies may have been a result of low concentrations of rela.xin in the granular cells and/or the presence of an immunochemically different relaxin molecule in these cells