The corpus luteum (CL) is under control of gonadotrophic hormones and produces progesterone, which is necessary for endometrial receptivity. Recent studies have shown that progesterone and its metabolites are involved in cell proliferation and apoptosis of cancer cells. Here weanalyzed the role of progesterone and its meta-bolites on luteinized granulosa cells (LGC) by FACS analysis and quantitative Real-Time PCR. We detected the mRNA of the progesterone metabolizing genes SRD5A1, AKR1C1, and AKR1C2 in LGC. The stimulation of LGC with progesterone or progesterone metabolites did not show any effect on the mRNA expression of these genes. However, a downregulation of Fas expression was found to be accomplished by progesterone and human chorionic gonadotropin. Our findings do not support the concept of an effect of progesterone metabolites on LGCs. However, it suggests an antiapoptotic effect of hCG and progesterone during corpus luteum development by downregulation of Fas.