Immunohistochemical localization of taurine in the rat ovary, oviduct, anduterus

The distribution of the amino acid taurine in the female reproductive organ s has not been previously analyzed in detail. The aim of this study was to determine taurine localization in the rat ovary, oviduct, and uterus by imm unohistochemical methods. Taurine was localized in the ovarian surface epit helium. The granulosa cells and oocytes of primordial follicles were immuno negative. In primary and antral follicles, taurine was found mainly in thec a cells and oocytes, whereas the zona pellucida, antrum, and most granulosa cells were unstained. However, taurine immunoreactivity in theca cells and oocytes decreased during follicular atresia. During corpora lutea developm ent, the number of immunopositive theca lutein cells increased as these cel ls invaded the granulosa-derived region. Therefore, most luteal cells from the mature corpora lutea were stained. In the regressing corpora lutea, how ever, taurine staining in luteal cells decreased. In the fimbriae, infundib ulum, and uterotubal junction, taurine was localized in most epithelial cel ls. In the ampullar and isthmic segments, taurine was found in the cilia of most ciliated cells and in the apical cytoplasm of some non-ciliated cells . In the uterus, most epithelial cells were immunopositive during diestrus and metestrus, whereas most of them were immunonegative during estrus and p roestrus. Moreover, taurine immunoreactivity in the oviduct and uterus decr eased with pregnancy.