Effect of antiprogestin RU 486 on the proliferation and metabolic activity of stromal cells separated from human endometrium.

The effects of RU 486 on the proliferation and metabolic activity of human endometrial stromal cells in culture were studied. RU 486 at 10(-7) M/well significantly stimulated (P < 0.001) the growth as well as metabolic activity in the culture system. Interestingly, RU 486 at 10(-6) M/well did not stimulate metabolic activity in the culture. Progesterone, in combination with RU 486 at 10(-7) M/well, caused a significant increase in proliferation (assessed by thymidine incorporation) (P < 0.001) over control and P4 alone, but not significantly different from RU 486 at 10(-7) M/well alone. The same pattern was observed for metabolic functions (assessed by uridine incorporation) when RU 486 at 10(-7) M/well, along with P4, was added to the culture. Interestingly, RU 486 at 10(-6) M/well with P4 had no effect on RNA synthesis in the culture. The relevance of these findings is discussed.