Activation of hypothalamic S6 kinase mediates diet-induced hepatic insulin resistance in rats

Hiraku Ono, Alessandro Pocai, Yuhua Wang, Hideyuki Sakoda, Tomoichiro Asano, Jonathan M. Backer, Gary J. Schwartz, Luciano Rossetti

Research output: Contribution to journalArticle

126 Scopus citations

Abstract

Prolonged activation of p70 S6 kinase (S6K) by insulin and nutrients leads to inhibition of insulin signaling via negative feedback input to the signaling factor IRS-1. Systemic deletion of S6K protects against diet-induced obesity and enhances insulin sensitivity in mice. Herein, we present evidence suggesting that hypothalamic S6K activation is involved in the pathogenesis of diet-induced hepatic insulin resistance. Extending previous findings that insulin suppresses hepatic glucose production (HGP) partly via its effect in the hypothalamus, we report that this effect was blunted by short-term high-fat diet (HFD) feeding, with concomitant suppression of insulin signaling and activation of S6K in the mediobasal hypothalamus (MBH). Constitutive activation of S6K in the MBH mimicked the effect of the HFD in normal chow-fed animals, while suppression of S6K by overexpression of dominant-negative S6K or dominant-negative raptor in the MBH restored the ability of MBH insulin to suppress HGP after HFD feeding. These results suggest that activation of hypothalamic S6K contributes to hepatic insulin resistance in response to short-term nutrient excess.

Original languageEnglish (US)
Pages (from-to)2959-2968
Number of pages10
JournalJournal of Clinical Investigation
Volume118
Issue number8
DOIs
StatePublished - Aug 1 2008

ASJC Scopus subject areas

  • Medicine(all)

Fingerprint Dive into the research topics of 'Activation of hypothalamic S6 kinase mediates diet-induced hepatic insulin resistance in rats'. Together they form a unique fingerprint.

  • Cite this