Direct Hepatocyte Insulin Signaling Is Required for Lipogenesis but Is Dispensable for the Suppression of Glucose Production. Author Paul Titchenell, William Quinn, Mingjian Lu, Qingwei Chu, Wenyun Lu, Changhong Li, Helen Chen, Bobby Monks, Julia Chen, Joshua Rabinowitz, Morris Birnbaum Publication Year 2016 Type Journal Article Abstract During insulin-resistant states such as type II diabetes mellitus (T2DM), insulin fails to suppress hepatic glucose production (HGP) yet promotes lipid synthesis. This metabolic state has been termed "selective insulin resistance" to indicate a defect in one arm of the insulin-signaling cascade, potentially downstream of Akt. Here we demonstrate that Akt-dependent activation of mTORC1 and inhibition of Foxo1 are required and sufficient for de novo lipogenesis, suggesting that hepatic insulin signaling is likely to be intact in insulin-resistant states. Moreover, cell-nonautonomous suppression of HGP by insulin depends on a reduction of adipocyte lipolysis and serum FFAs but is independent of vagal efferents or glucagon signaling. These data are consistent with a model in which, during T2DM, intact liver insulin signaling drives enhanced lipogenesis while excess circulating FFAs become a dominant inducer of nonsuppressible HGP. Keywords Animals, Signal Transduction, Gene Expression Regulation, Gene Deletion, Multiprotein Complexes, Glucose, Male, Mice, Knockout, Diet, TOR Serine-Threonine Kinases, Adipose Tissue, Hepatocytes, Insulin, Insulin Resistance, Mechanistic Target of Rapamycin Complex 1, Liver, Lipogenesis, Glucokinase, Efferent Pathways, Fatty Acids, Nonesterified, Forkhead Box Protein O1, Glucagon, Gluconeogenesis, Glucose Tolerance Test, Heparin, Postprandial Period, Proto-Oncogene Proteins c-akt, Vagus Nerve Journal Cell Metab Volume 23 Issue 6 Pages 1154-1166 Date Published 2016 Jun 14 ISSN Number 1932-7420 DOI 10.1016/j.cmet.2016.04.022 Alternate Journal Cell Metab PMCID PMC4909537 PMID 27238637 PubMedPubMed CentralGoogle ScholarBibTeXEndNote X3 XML