Carbonic anhydrase isoenzymes in normal human endometrium and erythrocytes

The total carbonic anhydrase activity of human endometrium doubled during the secretory phase of the menstrual cycle. Erythrocytes contained two isoenzymes that were also found in both proliferative and secretory phase endometrium, although these carbonic anhydrases were unaffected by hormonal changes that accompanied the normal menstrual cycle. In contrast, secretory phase endometrium contained a uterine-specific isoenzyme that was present only during the luteal phase of the menstrual cycle.