VITAMIN-D INDUCES PROLIFERATION IN RAT EN DOMETRIUM CULTURED-CELLS

Objective. To study the effects of 1,25-dihydroxyvitaminD3 (1,25-(OH)( 2)D-3) on proliferation and cell death in the rat uterus. Material and methods. A rat endometrial cell line (Rentro 1) grown in a Dulbecco M inimal Essential Medium (DMEM) supplemented with 1% charcoal stripped serum was used in all experiments in order to eliminate the steroid ho rmone. Cell monolayer was incubated in the presence and absence of 1,2 5-(OH)(2)D-3 or 17 beta-estradiol or vehicle. After stimulation, we ev aluated cell proliferation and DNA syntesis by trypan blue counting me thod and flow cytofluorometry, respectively. Finally, the genomic DNA integrity was evaluated by electrophoresis and the bands visualized wi th ultraviolet light. Results. The cells in medium containing 1% fetal bovine serum free of steroid hormones stimulated the cell growth 85% more than without serum. Supplement with albumin did not allow cell gr owth. The cells did not respond to 17 beta-estradiol but the presence of 1,25-(OH)2D3 induced cell proliferation. These results confirm that Rentro 1 cells do not express the estrogen receptor and demonstrate t heir capacity to respond to 1,25-(OH)(2)D-3. Finally, the integrity of DNA was not affected by 1,25-(OH)(2)D-3, suggesting that this hormone is not involved in cell death by apoptosis in our cell line, as seen in other cell lines. Conclusions. 1) 1,25-dihydroxyvitamin D induced c ell proliferation in the endometrial cell line Rentro 1 in a dose-depe ndent fashion and this effect is independent of the presence of an est rogenic stimulus; 2) the increase in cell number was related to DNA sy nthesis during the cell cycle; and 3) the presence of the hormone in t he culture medium was not able to induce cell death.