Effects of adrenaline on whole-body glucose metabolism and insulin-mediated regulation of glycogen synthase and PKB phosphorylation in human skeletal muscle

Research output: Contribution to journalArticlepeer-review

Authors

  • Jørgen Jensen
  • Yu-Chiang Lai
  • Toralph Ruge
  • Maria K. Svensson
  • Jan W. Eriksson

Colleges, School and Institutes

External organisations

  • Natl. Inst. of Occupational Health
  • Norwegian University of Sport and Physical Education
  • Umeå University Hospital
  • Sahlgrenska University Hospital
  • AstraZeneca

Abstract

In the present study, we investigated the effect of adrenaline on insulin-mediated regulation of glucose and fat metabolism with focus on regulation of skeletal muscle PKB, GSK-3, and glycogen synthase (GS) phosphorylation. Ten healthy subjects (5 men and 5 women) received a 240-minute intravenous infusion of adrenaline (0.05 μg/[kg min]) or saline; after 120 minutes, a hyperinsulinemic-euglycemic clamp was added. Adrenaline infusion increased blood glucose concentration by approximately 50%, but the hyperinsulinemic clamp normalized blood glucose within 30 minutes. Glucose infusion rate during the last hour was approximately 60% lower during adrenaline infusion compared with saline (4.3 ± 0.5 vs 11.2 ± 0.6 mg/kg lean body mass per minute). Insulin increased PKB Ser473, PKB Thr 308, and GSK-3β Ser9 phosphorylation in skeletal muscles; coinfusion of adrenaline did not influence insulin-stimulated PKB and GSK-3 phosphorylation. Adrenaline alone did not influence phosphorylation of PKB and GSK-3β. Insulin increased GS fractional activity and decreased GS Ser641 and Ser645,649,653,657 phosphorylation. In the presence of adrenaline, insulin did neither activate GS nor dephosphorylate GS Ser641. Surprisingly, GS Ser7 phosphorylation was not influenced by adrenaline. Adrenaline increased plasma lactate concentration; and muscle glycogen content was reduced in skeletal muscle the day after adrenaline infusion, supporting that insulin does not stimulate glycogen synthesis in skeletal muscles when adrenaline is present. In conclusion, adrenaline did not influence basal or insulin-stimulated PKB and GSK-3β phosphorylation in muscles, but completely blocked insulin-mediated GS activation and Ser 641 dephosphorylation. Still, insulin normalized adrenaline-mediated hyperglycemia.

Details

Original languageEnglish
Pages (from-to)215-226
Number of pages12
JournalMetabolism: Clinical and Experimental
Volume60
Issue number2
Early online date12 Feb 2010
Publication statusPublished - 1 Feb 2011