Abstract: 413

THE EFFECT OF GLUCOCORTICOIDS ON OVARIAN STEROIDOGENESIS AND APOPTOSIS.

Ravid Sasson¹ , K Hosokawa^{1 2} , A Dantes¹ , YS Jung¹ , A Amsterdam^{1 *}
Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel ¹
Department of OB/GYN, Fukui Medical University, Fukui, Japan ²

A possible role of glucocorticoids in ovarian steroidogenesis and apoptosis was studied in human granulosa cell (GC) line and in primary rat and human preovulatory GC. The human GC line (HO-23) was established by triple transfection of cells obtained from IVF patients with SV40 DNA, Ha-Ras oncogene and a temperature-sensitive mutant of the tumor suppressor gene p53 (p53 Val 135) (Hosokawa et al, 1998 Endocrinology 139: 4679-4687). Addition of dexamethasone (30 nM) or hydrocortisone (30 nM) to HO-23 cells or to primary rat or human preovulatory GC caused a synergistic effect on gonadotropin/cAMP induced progesterone production. This effect was abolished by RU486, indicating an a type glucocorticoid receptor expressed in GC. Dexamethasone dramatically inhibited apoptosis (60%) in HO-23 and primary GC, exerted by serum deprivation, by activation of the tumor suppressor gene p53 and by excess of cAMP stimulation. In western blot analysis, following dexamethasone stimulation, we observed 20 time increase in total cadherin expression using anti P-cadherin antibodies and 4-fold increase in N-cadherin synthesis using anti-N-cadherin antibodies. Dexamethasone treatment increased formation of adherence junction as revealed in electron microscopical inspection of ultrathin sections of the cells. Dexamethasone also increased formation of the anti apoptotic gene product BCL2. Cells treated with dexamethasone showed also a more developed actin cytoskeleton compared to non treated cells. We suggest that enhancement of cell contacts proteins and BCL2 is important in suppression of apoptosis in highly steroidogenic granulosa cells. Moreover stabilizing of cell contacts exerts its effect in concert with BCL2 in rescuing the cells from entry into the apoptotic pathway.

    This abstract is being presented on Tuesday, August 3 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.