Central melanocortin signaling restores skeletal muscle AMP-activated protein kinase phosphorylation in mice fed a high-fat diet

Cell Metab. 2007 May;5(5):395-402. doi: 10.1016/j.cmet.2007.04.004.

Abstract

Little is known about the role of the central melanocortin system in the control of fuel metabolism in peripheral tissues. Skeletal muscle AMP-activated protein kinase (AMPK) is activated by leptin and serves as a master regulator of fatty acid beta-oxidation. To elucidate an unidentified role of the central melanocortin system in muscle AMPK regulation, we treated conscious, unrestrained mice intracerebroventricularly with the melanocortin agonist MT-II or the antagonist SHU9119. MT-II augmented phosphorylation of AMPK and its target acetyl-CoA carboxylase (ACC) independent of caloric intake. Conversely, AMPK/ACC phosphorylation by leptin was abrogated by the coadministration of SHU9119 or in KKA(y) mice, which centrally express endogenous melanocortin antagonist. Importantly, high-fat-diet-induced attenuation of AMPK/ACC phosphorylation in leptin-overexpressing transgenic mice was not reversed by central leptin but was markedly restored by MT-II. Our data provide evidence for the critical role of the central melanocortin system in the leptin-skeletal muscle AMPK axis and highlight the system as a therapeutic target in leptin resistance.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinase Kinases
  • Analysis of Variance
  • Animals
  • Blotting, Western
  • Dietary Fats
  • Leptin / metabolism
  • Melanocortins / agonists
  • Melanocortins / antagonists & inhibitors
  • Melanocortins / metabolism*
  • Melanocyte-Stimulating Hormones / pharmacology
  • Metallothionein / pharmacology
  • Mice
  • Muscle, Skeletal / metabolism*
  • Phosphorylation / drug effects
  • Protein Kinases / metabolism*
  • Signal Transduction / physiology*

Substances

  • Dietary Fats
  • Leptin
  • Melanocortins
  • SHU 9119
  • Melanocyte-Stimulating Hormones
  • Metallothionein
  • Protein Kinases
  • AMP-Activated Protein Kinase Kinases