Histochemical detection of monoamine oxidases in rat female genital organs during preimplantation period of pregnancy

Localization of monoamine oxidases (MAO) in rat female gonads during preimplantation period of pregnancy was determined. Pregnant females were killed on their first, third, and fifth days of pregnancy and animals were transcardially perfused with PBS and fixative solutions. Ovaries, oviducts and uteri were immediately removed and they served for the determination of MAO localization employing the method of enzymatic histochemistry. MAO-A activity in ovary was visible in corpora lutea and in interstitial gland cells while MAO-B was detected predominantly in blood vessels. Both MAO enzymes were seen in the smooth muscle fibers of the ovarian hilum. The presence of MAO enzymes was however not detected in follicles at any stage of their development. In oviduct and uterus, both MAO enzymes were visible in similar places, namely in smooth muscle fibers, mast cells and blood vessels, with no MAO presence seen in the epithelium. Potential physiological importance of MAO localization in different cells of female reproductive organs during early period of pregnancy is proposed (Fig. 6, Ref. 29).