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 gr anulosa cells in culture. The AT(2) content was not changed by follicl e stimulating hormone (FSH), a differentiation factor of granulosa cel ls, but was markedly increased in FSH-free media. The cells cultured w ithout 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 PD12331 9 but not by Dup753, an antagonist specific for type 1 receptor, sugge sting that AII up-regulates the AT(2) expression via AT(2) itself. The se data strongly support the hypothesis that AT(2) might modulate the onset and progression of follicle atresia involving apoptosis Of granu losa cells. (C) 1995 Academic Press, Inc.