Glycogen Synthase Kinase 3α-Specific Regulation of Murine Hepatic Glycogen Metabolism Academic Article uri icon

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abstract

  • Glycogen synthase kinase 3 comprises two isoforms (GSK-3alpha and GSK-3beta) that are implicated in type II diabetes, neurodegeneration, and cancer. GSK-3 activity is elevated in human and rodent models of diabetes, and various GSK-3 inhibitors improve glucose tolerance and insulin sensitivity in rodent models of obesity and diabetes. Here, we report the generation of mice lacking GSK-3alpha. Unlike GSK-3beta mutants, which die before birth, GSK-3alpha knockout (GSK-3alpha KO) animals are viable but display enhanced glucose and insulin sensitivity accompanied by reduced fat mass. Fasted and glucose-stimulated hepatic glycogen content was enhanced in GSK-3alpha KO mice, whereas muscle glycogen was unaltered. Insulin-stimulated protein kinase B (PKB/Akt) and GSK-3beta phosphorylation was higher in GSK-3alpha KO livers compared to wild-type littermates, and IRS-1 expression was markedly increased. We conclude that GSK-3 isoforms exhibit tissue-specific physiological functions and that GSK-3alpha KO mice are insulin sensitive, reinforcing the potential of GSK-3 as a therapeutic target for type II diabetes.

authors

  • MacAulay, Katrina
  • Doble, Bradley
  • Patel, Satish
  • Hansotia, Tanya
  • Sinclair, Elaine M
  • Drucker, Daniel J
  • Nagy, Andras
  • Woodgett, James R

publication date

  • October 2007