Peroxidase activity in glands and stroma of human endometrium

Peroxidase activity was measured in specimens of human endometrium taken at different days of the menstrual cycle. High specific activities were more frequently found in secretory endometrium than in proliterative tissue, but the variance at each phase of the cycle was large and differences were statistically not significant. The results obtained do not support the hypothesis that peroxidase activity is determined by the levels of circulating estrogens, as is apparently true in rats. Extremely high levels of peroxidase activity were noticed in some, but not all, specimens of endometrial adenocarcinoma. Endometrial glands were separated from the stroma after collagenase digestion of normal and abnormal endometrial glands were separated from the stroma after collagenase digestion of normal and abnormal endometrium, and peroxidase activity was measured in each fraction. The enzyme was found to be preferentially localized in the stroma, in contrast to the reported findings of predominantly epithelial localization in the rat.