[Estradiol and progesterone receptors in human endometrium during the menstrual cycle]

The concentrations of estradiol and progesterone receptors are measured in the cytoplasmic and nuclear fractions of endometrial samples obtained by biopsy throughout the menstrual cycle. The standardized micromethod accounts for the sites occupied by endogenous hormones and for interference by androgen receptors and plasma binding proteins. In normal women, the cellular concentration of estradiol receptor increases early in the cycle and decreases steadily after ovulation. The progesterone receptor is maximum between the 10th and 15th day of the cycle and decreases during the luteal phase. The nuclear/cytoplasmic ratios of both receptors follow the variations of circulating hormones. These data constitute a new basis for physiopathological and pharmacological investigations on the hormonal control of the human uterus.