Reduced melanocortin production causes sexual dysfunction in male mice with POMC neuronal insulin and leptin insensitivity

Endocrinology. 2015 Apr;156(4):1372-85. doi: 10.1210/en.2014-1788. Epub 2015 Jan 15.

Abstract

Proopiomelanocortin (POMC)-derived peptides like α-melanocyte-stimulating hormone (MSH) substantially improve hepatic insulin sensitivity and regulate energy expenditure. Melanocortinergic agents are also powerful inducers of sexual arousal that are being investigated for a possible therapeutic role in erectile dysfunction. It is currently unclear whether reduced melanocortin (MC) activity may contribute to the sexual dysfunction accompanying obesity and type 2 diabetes. Male rodents with leptin and insulin resistance targeted to POMC neurons (leptin receptor [LepR]/insulin receptor [IR]POMC mice) exhibit obesity, hyperinsulinemia, hyperglycemia, and systemic insulin resistance. In this study, we demonstrate that LepR/IRPOMC males are also subfertile due to dramatic alterations in sexual behavior. Remarkably, these reproductive changes are accompanied by decreased α-MSH production not present when a single receptor type is deleted. Unexpectedly, behavioral sensitivity to α-MSH and MC receptor expression are also reduced in LepR/IRPOMC males, a potential adaptation of the MC system to altered α-MSH production. Together, these results suggest that concurrent insulin and leptin resistance in POMC neurons in individuals with obesity or type 2 diabetes can reduce endogenous α-MSH levels and impair sexual function.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aggression / physiology
  • Animals
  • Insulin / metabolism
  • Insulin Resistance / physiology
  • Leptin / metabolism
  • Male
  • Melanocortins / metabolism*
  • Mice
  • Mice, Knockout
  • Neurons / metabolism*
  • Pro-Opiomelanocortin / metabolism*
  • Receptor, Insulin / genetics
  • Receptor, Insulin / metabolism*
  • Receptors, Leptin / genetics
  • Receptors, Leptin / metabolism*
  • Sexual Dysfunction, Physiological / genetics
  • Sexual Dysfunction, Physiological / metabolism*

Substances

  • Insulin
  • Leptin
  • Melanocortins
  • Receptors, Leptin
  • Pro-Opiomelanocortin
  • Receptor, Insulin