Role for Prostaglandins in the Regulation of Type 1 11β-Hydroxysteroid Dehydrogenase in Human Granulosa-Lutein Cells

Abstract

11β-Hydroxysteroid dehydrogenase (11βHSD) enzymes regulate glucocorticoid availability in target tissues. 11βHSD1 is the predominant isoenzyme expressed and active in human granulosa-lutein (hGL) cells. This study investigated the effects of pharmacological inhibitors of prostaglandin (PG) synthesis on 11βHSD1 activities and expression in hGL cells. The consequences for 11βHSD1 of increasing exposure of hGL cells to PGs, either by treatment with exogenous PGs or by challenging cells with IL-1β, were also assessed. Suppression of basal PG synthesis using four different inhibitors of PG H synthase enzymes [indomethacin, niflumic acid, meclofenamic acid (MA) and N-(2-cyclohexyloxy-4-nitorophenyl) methane sulfonamide (NS-398)] each resulted in significant decreases in both cortisol oxidation and cortisone reduction. Both activities of 11βHSD1 were suppressed by up to 64 ± 6% (P < 0.05). Over 4 and 24 h, neither MA nor NS-398 affected the expression of 11βHSD1 protein, suggesting enzyme regulation by PGs at the posttranslational level. When cells were cotreated for 4 h with PGHS inhibitors plus 30 nm PGD2, PGF2α, or PGE2, each PG overcame the suppression of cortisol oxidation by indomethacin or MA. Treatment of hGL cells with IL-1β increased the concentrations of both PGE2 and PGF2α, accompanied by a 70 ± 25% increase in net cortisol oxidation. All three responses to IL-1β were abolished when cells were cotreated with MA. These findings suggest a role for PGs in the posttranslational regulation of 11βHSD1 activities in hGL cells.