Glycogen metabolism of the human endometrium.

The glycogen concentration and the activities of glycogen synthetase and phosphorylase were assayed in endometrial tissue obtained during curettage. Tissues were obtained during different phases of the menstrual cycle from women investigated because of menometrorrhagia or sterility. The glycogen concentration was less than 2 mg/g wet wt in specimens from days 1-15 and increased 10-fold during the early secretory phase. The total activities of glycogen synthetase and phosphorylase were increased 1.5- and 2-fold, respectively, during the secretory phase compared to those during the first half of the cycle. The activities of the active forms (a form) of these enzymes did not show significant changes during the menstrual cycle. The largest difference between the proliferative and secretory phases was in the activity of glycogen synthetase phosphatase, which was virtually inactive in tissues obtained on days 1-15 and increased almost 20-fold during the secretory part of the cycle. In tissues obtained from cases of sterility, the activities of glycogen synthetase and phosphorylase were significantly reduced only during the early secretory phase. Glycogen concentration throughout the menstrual cycle and enzyme activities during the midsecretory and premenstrual phase were similar in cases of sterility and other pathologies.