Activins regulate 17 beta-hydroxysteroid dehydrogenase type I transcription in murine gonadotrope cells

作者:Bak Beata; Carpio Laura; Kipp Jinjing L; Lamba Pankaj; Wang Ying; Ge Ren Shan; Hardy Matthew P; Mayo Kelly E; Bernard Daniel J*
来源:Journal of Endocrinology, 2009, 201(1): 89-104.
DOI:10.1677/JOE-08-0460

摘要

Activins are pleiotropic members of the TGF beta superfamily and were initially characterized based on their abilities to stimulate FSH synthesis and secretion by gonadotrope cells of the anterior pituitary gland. Here, we identified the gene encoding the steroidogenic enzyme, 17 beta-hydroxysteroid dehydrogenase type I (17 beta-HSD1; Hsd17b1), as an activin-responsive gene in immortalized gonadotrope cells, L beta T2. 17 beta-HSD1 catalyzes the conversion of estrone to the more active 17 beta-estradiol, and activin A stimulated an increase in this enzymatic activity in these cells. We demonstrated that activins signaled via the type I receptor, activin receptor-like kinase (ALK4), and the intracellular signaling protein, SMAD2, to regulate Hsd17b1 transcription in immediate-early fashion. Critical cis-elements, including a minimal SMAD-binding element, were mapped to within 100 bp of the start of transcription. Activin/ALK4 signaling also regulated Hsd17b1 transcription in both immortalized and primary cultured murine granulosa cells. The promoter regions mediating basal and activin/ALK4-regulated promoter activity were generally conserved across the different cell types. The data show chat activin A rapidly regulates Hsd17b1 transcription in gonadotrope and granulosa cells and may thereby regulate local 17 beta-estradiol synthesis. Journal of Endocrinology (2009) 201, 89-104