title: Metformin-induced stimulation of adenosine 5' monophosphate-activated protein kinase (PRKA) impairs progesterone secretion in rat granulosa cells.
abstract: Metformin is an anti-diabetic drug commonly used to treat cycle disorders and anovulation in women with polycystic ovary syndrome. However, the effects and molecular mechanism of metformin in the ovary are not entirely understood. We investigated the effects of this drug on steroidogenesis and proliferation in rat granulosa cells. Metformin (10 mM) treatment for 48 h reduced progesterone and estradiol (E2) production in both basal conditions and under FSH stimulation. It also decreased the levels of the HSD3B, CYP11A1, STAR, and CYP19A1 proteins in response to FSH (10(-8) M) and of HSD3B in the basal state only. Metformin treatment (10 mM, 24 h) also reduced cell proliferation and the levels of CCND2 and CCNE proteins without affecting cell viability, both in the basal state and in response to FSH. Furthermore, metformin treatment for 1 h simultaneously increased the Thr172 phosphorylation of PRKAA (adenosine 5' monophosphate-activated protein kinase alpha) and the Ser79 phosphorylation of ACACA (acetyl-Coenzyme A carboxylase alpha). The adenovirus-mediated production of dominant-negative PRKAA totally abolished the effects of metformin on progesterone secretion, HSD3B and STAR protein production, and MAPK3/1 phosphorylation. Conversely, total inhibition of PRKAA Thr172 phosphorylation with the dominant-negative PRKAA adenovirus did not restore the decrease in E2 production and cell proliferation induced by metformin. Our results therefore strongly suggest that metformin reduces progesterone production via a PRKAA-dependent mechanism, whereas PRKAA activation is not essential for the decrease in E2 production and cell growth induced by metformin in rat granulosa cells.
authors.affiliation: Unité de Physiologie de la Reproduction et des Comportements, Institut National de la Recherche Agronomique, 37380 Nouzilly, France.
authors.forename: Lucie
authors.initials: L
authors.lastname: Tosca
authors.forename: Patricia
authors.initials: P
authors.lastname: Solnais
authors.forename: Pascal
authors.initials: P
authors.lastname: Ferré
authors.forename: Fabienne
authors.initials: F
authors.lastname: Foufelle
authors.forename: Joëlle
authors.initials: J
authors.lastname: Dupont
mesh_terms: D000103:Acetyl-CoA Carboxylase / Q000378:metabolism; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D015153:Blotting, Western; D049109:Cell Proliferation; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D004958:Estradiol / Q000378:metabolism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D005822:Genetic Vectors; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D008687:Metformin / Q000494:pharmacology*; D010766:Phosphorylation; D011374:Progesterone / Q000096:biosynthesis / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D013256:Steroids / Q000096:biosynthesis; D013936:Thymidine / Q000378:metabolism
chemical_list: D007004:Hypoglycemic Agents; D013256:Steroids; D011374:Progesterone; D004958:Estradiol; D005640:Follicle Stimulating Hormone; D008687:Metformin; D017868:Cyclic AMP-Dependent Protein Kinases; D000103:Acetyl-CoA Carboxylase; D013936:Thymidine