Effect of endothelin-1 on the biological changes of the corpus luteum regression process

The present study was conducted to evaluate whether apoptosis occurs during the corpus luteum (CL) regression process in rats, and, if so, to determine the effect of endothelin-1 (ET-1) in this process. In order to obtain CL cells, immature female rats were treated with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) to cause hyperovulation. CL cells were treated with three different dosages of ET-1 (1.0 x 10(-5) M, 1.0 x 10(-7) M, and 1.0 x 10(-9) M). The occurrence of apoptosis, intracellular calcium concentrations, and progesterone production were measured to determine the biological changes in the CL cells. We found that apoptosis occurs during CL regression accompanied by an increase in intracellular calcium, while progesterone production was decreased. ET-1 promotes the apoptosis through an increase in the intracellular calcium in the CL cells and affects the physiological function of CL cells by inhibiting progesterone production. ET-1 was shown to be an important regulator of CL during its regression.