Ovarian steroids reduced apoptotic death in SV40 temperature-sensitive mutant virus transformed uterine epithelial...

Ovarian steroids have been shown to inhibit uterine cell death in vivo. In this study, we investigated whether ovarian steroids regulated cell death in an uterine epithelial cell line transformed with SV40 temperature-sensitive (ts) mutant virus. To assess cell death rate, cells were grown at permissive temperature (34 degrees C) and pulsed with 3H-thymidine. The retention of incorporated radioactivity was then examined after a temperature shift to nonpermissive temperature (40 degrees C) in the absence or presence of estradiol and progesterone. When cells were continuously cultured at 34 degrees C, cell number increased rapidly and most of radioactivity was retained in the attached cells. However, the temperature shift from 34 degrees C to 40 degrees C resulted in a decrease in cell number and radioactivity in attached cells. Estradiol and progesterone attenuated this temperature shift-induced cell death. Morphological examination with Hoechst 33258 staining revealed that the temperature shift increased the percentage of apoptotic death. The treatment of ovarian steroids reduced the extent of apoptotic death. Our studies demonstrated that ovarian steroids could act directly on uterine epithelial cells to reduce apoptotic death in culture.