ABSTRACT
The effects of ovariectomy and exogenous gonadal hormones on uterine enzymes have been examined for several laboratory mammals. Qualitative and quantitative measurement of uterine and placental enzymes involve histochemical, cytochemical and biochemical techniques. Enzymes have a wide and characteristic distribution in the female reproductive tract. The pattern of distribution varies showing peculiar species – specific differences in the anatomical localization of the enzyme and its relationship to the reproductive cycle. Progestational responses involve major endometrial growth and striking change in the enzyme system. The amount and biochemical composition of endometrial secretions vary with the stage of reproductive cycle. The placenta contains a complex enzyme system which has been classified into five major groups: hydrases, transferases, oxidoreductases, lyases and isomerases. The passage of many substances across the placental barrier is chemically regulated; the cytoplasm of barrier contains several enzymes and organelles. Carbonic anhydrase activity of the endometrium increases markedly during the luteal phase of the cycle and during pregnancy in the rabbit but not in some other species. Alkaline phosphatase is widely distributed in all types of placenta, in maximal concentration in species producing no fructose. Several hydrolytic enzymes are associated with the small cytoplasmic particles, the lysosomes, β-glucuronidase of the endometrial and glandular epithelia shows cyclical changes with the oestrus cycle. The activity of the succinic dehydrogenase may be an index of the functional status of the epithelial cells. Some enzymes e. g. acid and alkaline phosphatase, 5-nucleotidase and adenosinetriphosphate show a typical »secretion cycle«. The role of certain uterine enzymes in implantation of blastocyst deserves investigation.
