title: Obesity-induced infertility and hyperandrogenism are corrected by deletion of the insulin receptor in the ovarian theca cell.
abstract: Women with polycystic ovary syndrome (PCOS) exhibit elevated androgen levels, oligoanovulation, infertility, and insulin resistance in metabolic tissues. The aims of these studies were to determine the role of insulin signaling in the development and function of ovarian theca cells and the pathophysiologic effects of hyperinsulinism on ovarian function in obesity. We disrupted the insulin receptor (IR) gene specifically in the theca-interstitial (TI) cells of the ovaries (Cyp17IRKO). No changes in reproductive development or function were observed in lean Cyp17IRKO female mice, suggesting that insulin signaling in TI cell is not essential for reproduction. However, when females were fed a high-fat diet, diet-induced obesity (DIO) wild-type (DIO-WT) mice were infertile and experienced increased circulating testosterone levels, whereas DIO-Cyp17IRKO mice exhibited improved fertility and testosterone levels comparable to those found in lean mice. The levels of phosphorylated IRS1 and CYP17 protein were higher in the ovary of DIO-WT compared with DIO-Cyp17IRKO or lean mice. Ex vivo studies using a whole ovary culture model demonstrated that insulin acts independently or additively with human chorionic gonadotropin to enhance androstenedione secretion. These studies reveal the causal pathway linking hyperinsulinism with ovarian hyperandrogenism and the infertility of obesity.
authors.affiliation: Division of Pediatric Endocrinology, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Sheng
authors.initials: S
authors.lastname: Wu
authors.forename: Sara
authors.initials: S
authors.lastname: Divall
authors.forename: Amanda
authors.initials: A
authors.lastname: Nwaopara
authors.forename: Sally
authors.initials: S
authors.lastname: Radovick
authors.forename: Fredric
authors.initials: F
authors.lastname: Wondisford
authors.forename: Chemyong
authors.initials: C
authors.lastname: Ko
authors.forename: Andrew
authors.initials: A
authors.lastname: Wolfe
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D017588:Hyperandrogenism / Q000209:etiology / Q000628:therapy*; D006946:Hyperinsulinism / Q000378:metabolism; D007247:Infertility, Female / Q000209:etiology*; D055504:Insulin Receptor Substrate Proteins / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009765:Obesity / Q000150:complications* / Q000503:physiopathology; D010053:Ovary / Q000502:physiology*; D011085:Polycystic Ovary Syndrome / Q000503:physiopathology; D011972:Receptor, Insulin / Q000172:deficiency*; D015398:Signal Transduction; D013254:Steroid 17-alpha-Hydroxylase / Q000235:genetics / Q000378:metabolism; D013739:Testosterone / Q000097:blood; D013799:Theca Cells / Q000502:physiology*; D046509:Tissue Culture Techniques
chemical_list: D055504:Insulin Receptor Substrate Proteins; C526295:Irs1 protein, mouse; D013739:Testosterone; D013254:Steroid 17-alpha-Hydroxylase; D011972:Receptor, Insulin