The AMP-activated protein kinase α2 catalytic subunit controls whole-body insulin sensitivity
Benoit Viollet, … , Rémy Burcelin, Sophie Vaulont
Benoit Viollet, … , Rémy Burcelin, Sophie Vaulont
Published January 1, 2003
Citation Information: J Clin Invest. 2003;111(1):91-98. https://doi.org/10.1172/JCI16567.
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Article Metabolism

The AMP-activated protein kinase α2 catalytic subunit controls whole-body insulin sensitivity

Abstract

AMP-activated protein kinase (AMPK) is viewed as a fuel sensor for glucose and lipid metabolism. To better understand the physiological role of AMPK, we generated a knockout mouse model in which the AMPKα2 catalytic subunit gene was inactivated. AMPKα2–/– mice presented high glucose levels in the fed period and during an oral glucose challenge associated with low insulin plasma levels. However, in isolated AMPKα2–/– pancreatic islets, glucose- and L-arginine–stimulated insulin secretion were not affected. AMPKα2–/– mice have reduced insulin-stimulated whole-body glucose utilization and muscle glycogen synthesis rates assessed in vivo by the hyperinsulinemic euglycemic clamp technique. Surprisingly, both parameters were not altered in mice expressing a dominant-negative mutant of AMPK in skeletal muscle. Furthermore, glucose transport was normal in incubated isolated AMPKα2–/– muscles. These data indicate that AMPKα2 in tissues other than skeletal muscles regulates insulin action. Concordantly, we found an increased daily urinary catecholamine excretion in AMPKα2–/– mice, suggesting altered function of the autonomic nervous system that could explain both the impaired insulin secretion and insulin sensitivity observed in vivo. Therefore, extramuscular AMPKα2 catalytic subunit is important for whole-body insulin action in vivo, probably through modulation of sympathetic nervous activity.

Authors

Benoit Viollet, Fabrizio Andreelli, Sebastian B. Jørgensen, Christophe Perrin, Alain Geloen, Daisy Flamez, James Mu, Claudia Lenzner, Olivier Baud, Myriam Bennoun, Emmanuel Gomas, Gaël Nicolas, Jørgen F.P. Wojtaszewski, Axel Kahn, David Carling, Frans C. Schuit, Morris J. Birnbaum, Erik A. Richter, Rémy Burcelin, Sophie Vaulont

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Figure 1

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Generation of mice lacking AMPKα2. (a) Schematic representation (not to ...
Generation of mice lacking AMPKα2. (a) Schematic representation (not to scale) of genomic structure of AMPKα2 wild-type allele, AMPKα2 gene-targeting construct, AMPKα2 targeted allele, and AMPKα2 null allele. Squares indicate loxP sites and H’s indicate HindIII restriction sites. C corresponds to the exon encoding the AMPKα2 catalytic domain (amino acids 189–260) (b) Southern blot analysis after HindIII digestion of tail DNA from offspring derived from heterozygous intercrosses. Expected fragment sizes of the AMPKα2 wild-type (+/+; 5.3 kb) and null (–/–; 3.8 kb) alleles after HindIII digestion and hybridization with the indicated probe (solid bar in a) are shown. (c) Western blot analysis of AMPKα1 and AMPKα2 proteins in liver and gastrocnemius muscle from control (+/+) and AMPKα2–/– mice. (d) Phosphorylation level of ACC in liver and gastrocnemius muscle from control and AMPKα2–/– mice.