Modulation of estrogen production and 17beta-hydroxysteroid dehydrogenase-type 1, cytochrome P450 aromatase, c-met, and protein kinase Balpha messenger ribonucleic acid content in rat ovarian granulosa cells by hepatocyte growth factor and follicle-stimulating hormone

Abstract

Hepatocyte growth factor (HGF) suppresses FSH-dependent estradiol-17beta (E(2)) production in ovarian granulosa cells (GC). The mechanisms of action for HGF in GC are unknown; however, activation of the HGF receptor, c-Met, can induce c-Akt/protein kinase B (PKB)-mediated signal transduction in nonovarian cells. Using immature rat GC, the present study investigated the effects of HGF within the estrogen biosynthetic pathway, concomitant with changes in c-Met and PKBalpha mRNA expression. Granulosa cells were incubated with androstenedione and FSH, HGF, and/or dibutyryl-cAMP (Bu(2)-cAMP). Follicle-stimulating hormone and Bu(2)-cAMP each stimulated estrone (E(1)) and E(2) synthesis at 48 h. Hepatocyte growth factor suppressed FSH-dependent E(2), but not E(1), synthesis. Semiquantitative reverse transcription-polymerase chain reaction showed that HGF impaired FSH-supported 17beta-hydroxysteroid dehydrogenase type-1 (17beta-HSD) and cytochrome P450 aromatase (P450arom) mRNA levels. Hepatocyte growth factor did not reduce E(2) synthesis or 17beta-HSD and P450arom mRNA expression in the presence of Bu(2)-cAMP at 48 h. The FSH and HGF each down-modulated c-Met mRNA accumulation, whereas Bu(2)-cAMP increased c-Met mRNA content. Between 0 and 48 h a biphasic change in PKBalpha mRNA content occurred with either FSH or HGF; however, PKBalpha mRNA accumulation was augmented by HGF. Collectively, results suggest that HGF can suppress E(2) production in GC by disrupting cAMP-dependent 17beta-HSD and P450arom. Changes in c-Met and PKBalpha mRNA content provide a potential link between HGF signaling and the FSH-dependent mechanisms that control the steroidogenic differentiation of GC.