Mechanism of Action of 2-Hydroxyestradiol on Steroidogenesis in Ovarian Granulosa Cells: Interactions with Catecholamines and Gonadotropins Involve Cyclic Adenosine Monophosphate1

Publisher Website
Google Scholar
Abstract
Previously we have shown that 2-hydroxyestradiol (2-OH-E2) synergizes with catecholamine to enhance progesterone production by porcine granulosa cells in vitro. The present studies were undertaken to determine if the synergistics effects of 2-OH-E2 and catecholamines were 1) modulated by gonodatroopins, 2) unique to catecholamines, and 3) mediated by cyclic adenosine monophosphate (cAMP). Undifferentiated granulosa cells from 1- to 3-mm porcine follicles were cultured in serum-free medium for periods of 6-9 days. A 3-day pretreatment plus a 4-day cotreatment verus a 4-day cotreatment of granulosa cells cultures with FSH did not significantly alter progesterone production stimulated by a saturating concentrations of epinephrine (EPI; 2 .mu.g/m) but significantly reduced the effect of 4 .mu.g/ml 2-OH-E2 on Day 7 of culture. Four-day cotreatment of either FSH or luteinizing hormone (LH) from Day 3 to 7 of culture dramatically enhanced progresterone production stimulated by 2-OH-E2 and estradiol (E2) but not by EPI when measured on Day 7 of culture. Progesterone production (expressed as "-fold of controls") stimulated by 4-day treatment of EPI, 2-OH-E2, or EPI-plus-2-OH-E2 was 1.4 .+-. 0.2, 8.2 .+-. 2.2, and 10.7 .+-. 1.0, respectively, in the presence of LH (n = 5 experiments), and 1.9 .+-. 0.1, 7.8 .+-. 1.4, and 10.6 .+-. 1.8, respectively, in the presence of FSH (n = 3 experiments). Similar to E2, 2-OH-E2 significantly enhanced the stimulating effect of the cAMP analog 8-bromo-cAMP (0.5 mM) on progesterone production. The synergism between saturating concentrations of 2-OH-E2 and EPI on progesterone production was not observed in the presence of 8-bromo-cAMP. However, the synergism between 2-OH-E2 and EPI persisted in the presence of of the phosphodiesterase inhibitor 3-isobutyl-1-methyl-xanthine (IBMX, 0.5 mM). In addition, cAMP accumulat over 24 h (medium plus cell extracts) stimulated by EPI or by FSH was significantly elevated i the presence of 2-OH-E2 but not E2. Collectively, these results suggest that 1) 2-OH-E2 can dramatically enhance LH- and FSH-stimulated progesterone production; 2) the synergism between 2-OH-E2 and gonadotropins was at least as great as that of the synergism between 2-OH-E2 and catecholamines; 3) in contrast to studies with ratgranulos cells, pretreatment of concurrent treatment of porcine granulosa cells with gonadotropins and catechalamines exerts, at best, an additive effect on the catecholalminergic respons; and 4) a major locus of 2-OH-E2 (but not E2)-potentiated progesterone production stimulated y EPI or FSH is exerted at the level of generation of cAMP.

This publication has 25 references indexed in Scilit: