[Variation in the number of estrogen and progesterone receptors in normal human endometrial cells in culture].

As estrogens are in vivo potent growth factors of their target cells but are ineffective in vitro on human endometrial cell multiplication, an eventual role of steroïd sex hormone receptors has been suspected. These receptors have been assayed in human endometrium, and cytoplasmic concentrations compared between fresh tissue, short term and long term cultures. Receptors remain present in culture but at a lower level than in vivo. Estrogen receptors keep stable with the duration of the culture while progesterone receptors progressively diminish. More, these receptors are active: estradiol administration induces a new progesterone receptor synthesis in culture. So, steroïd sex hormone receptors do not seem to be involved in the ineffectiveness of estrogens on cell multiplication in culture.