Activity of deoxyribonucleic acid polymerase alpha stimulated by estrogen in the endometrium of the human uterus during the menstrual cycle.

To provide some insight into how deoxyribonucleic acid (DNA) synthesis occurs in the endometrium of the human uterus during the menstrual cycle, the DNA polymerase activities (alpha and beta) in endometrial samples taken from normal cycling women, and the concentration of estradiol-17 beta (E2) and progesterone in the serum were measured. DNA polymerase alpha activity increased gradually from the beginning of the menstrual cycle, reaching a peak 2-3 days before ovulation, and then showed a decrease. Increase in this activity occurred in parallel with that of the concentration of E2, but not progesterone, in the serum sample in the proliferative phase (correlation coefficient r = 0.924, p less than 0.001). In contrast, DNA polymerase alpha activity stimulated by estrogen in the endometrium of the 2nd grade amenorrheal women decreased abruptly after an injection of 125 mg progesterone. DNA polymerase beta activity showed no significant change during the menstrual cycle or after estrogen and progesterone treatment. These results suggest that estrogen seems to stimulate the induction of DNA polymerase alpha activity during cell proliferation in the endometrium of the human uterus.