HORMONAL-REGULATION OF PROLIFERATION IN 2 POPULATIONS OF RABBIT ENDOMETRIAL CELLS IN CULTURE

We have previously described a technique to culture rabbit primary endometrium epithelial cells in chemically defined medium, whose proliferation was determined to respond to estrogens and progesterone. The cultures were found to be made up of two cell populations: quiescent and dividing cells. We describe here techniques to select for these two cell populations using 3H-thymidine and cytosine arabinoside or Colcemid. The quiescent cells were found to be the only target for the growth-promoting effect of estrogens. Epidermal growth factor and prostaglandin F-2α stimulated the proliferation of both cell populations. Progesterone was found not to antagonize the effect of estrogen on the quiescent cells unless the hormone was incubated previously with a mixed cell culture. This finding suggests the existence of a progesterone putative factor (PPF) resulting from the interaction of progesterone and dividing cells which is involved in the inhibition of the estrogenic effect on endometrial cell proliferation. Two other progestins were not found to have the same effect as progesterone, showing the specificity of this ovarian hormone action. © 1979.