title: Insulin receptor signaling in the GnRH neuron plays a role in the abnormal GnRH pulsatility of obese female mice.
abstract: Infertility associated with obesity is characterized by abnormal hormone release from reproductive tissues in the hypothalamus, pituitary, and ovary. These tissues maintain insulin sensitivity upon peripheral insulin resistance. Insulin receptor signaling may play a role in the dysregulation of gonadotropin-releasing hormone (GnRH) secretion in obesity, but the interdependence of hormone secretion in the reproductive axis and the multi-hormone and tissue dysfunction in obesity hinders investigations of putative contributing factors to the disrupted GnRH secretion. To determine the role of GnRH insulin receptor signaling in the dysregulation of GnRH secretion in obesity, we created murine models of diet-induced obesity (DIO) with and without intact insulin signaling in the GnRH neuron. Obese control female mice were infertile with higher luteinizing hormone levels and higher GnRH pulse amplitude and total pulsatile secretion compared to lean control mice. In contrast, DIO mice with a GnRH specific knockout of insulin receptor had improved fertility, luteinizing hormone levels approaching lean mice, and GnRH pulse amplitude and total secretion similar to lean mice. Pituitary responsiveness was similar between genotypes. These results suggest that in the obese state, insulin receptor signaling in GnRH neurons increases GnRH pulsatile secretion and consequent LH secretion, contributing to reproductive dysfunction.
authors.affiliation: Department of Pediatrics, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Sara A
authors.initials: SA
authors.lastname: DiVall
authors.affiliation: Department of Pediatrics, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Danny
authors.initials: D
authors.lastname: Herrera
authors.affiliation: Department of Pediatrics, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Bonnie
authors.initials: B
authors.lastname: Sklar
authors.affiliation: Department of Pediatrics, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Sheng
authors.initials: S
authors.lastname: Wu
authors.affiliation: Department of Pediatrics, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Fredric
authors.initials: F
authors.lastname: Wondisford
authors.affiliation: Department of Pediatrics, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Sally
authors.initials: S
authors.lastname: Radovick
authors.affiliation: Department of Pediatrics, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Andrew
authors.initials: A
authors.lastname: Wolfe
mesh_terms: D000818:Animals; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007247:Infertility, Female / Q000150:complications / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000097:blood; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008820:Mice, Obese; D009765:Obesity / Q000150:complications / Q000378:metabolism; D010053:Ovary / Q000378:metabolism; D011972:Receptor, Insulin / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction
chemical_list: D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D011972:Receptor, Insulin