CHARACTERIZATION OF ANGIOTENSIN-II RECEPTOR TYPE-2 DURING DIFFERENTIATION AND APOPTOSIS OF RAT OVARIAN CULTURED GRANULOSA-CELLS

We examined the change in the content of angiotensin II (AII) receptor type 2 (AT(2)) during differentiation and apoptosis of rat ovarian granulosa cells in culture. The AT(2) content was not changed by follicle stimulating hormone (FSH), a differentiation factor of granulosa cells, but was markedly increased in FSH-free media. The cells cultured without FSH underwent internucleosomal DNA fragmentation characteristic of apoptosis, which occurs during follicle atresia. AII augmented the increase in the AT(2) content in the absence of FSH. This AII-induced augmentation was suppressed by the AT(2)-selective antagonist PD123319 but not by Dup753, an antagonist specific for type 1 receptor, suggesting that AII up-regulates the AT(2) expression via AT(2) itself. These data strongly support the hypothesis that AT(2) might modulate the onset and progression of follicle atresia involving apoptosis Of granulosa cells. (C) 1995 Academic Press, Inc.