5-Aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) effect on glucose production, but not energy metabolism, is independent of hepatic AMPK in vivo

Clinton M. Hasenour, D. Emerson Ridley, Curtis C. Hughey, Freyja D. James, E. Patrick Donahue, Jane Shearer, Benoit Viollet, Marc Foretz, David H. Wasserman

Research output: Contribution to journalArticle

38 Scopus citations

Abstract

Metabolic stress, as well as several antidiabetic agents, increases hepatic nucleotide monophosphate (NMP) levels, activates AMP-activated protein kinase (AMPK), and suppresses glucose production. We tested the necessity of hepatic AMPK for the in vivo effects of an acute elevation in NMP on metabolism. 5-Aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR; 8 mg·kg-1·min-1)-euglycemic clamps were performed to elicit an increase inNMPin wild type (α1α2 lox/lox) and liver-specific AMPK knock-out mice (α1α 2lox/lox + Albcre) in the presence of fixed glucose. Glucose kinetics were equivalent in 5-h fasted α1α2lox/lox and α1α2lox/lox + Albcre mice. AMPK was not required for AICAR-mediated suppression of glucose production and increased glucose disappearance. These results demonstrate that AMPK is unnecessary for normal 5-h fasting glucose kinetics and AICAR-mediated inhibition of glucose production. Moreover, plasma fatty acids and triglycerides also decreased independently of hepatic AMPK during AICAR administration. Although the glucoregulatory effects of AICAR were shown to be independent of AMPK, these studies provide in vivo support for the AMPK energy sensor paradigm. AICAR reduced hepatic energy charge by ∼20% in α1α2lox/lox, which was exacerbated by ∼2-fold in α1α2lox/lox + Albcre. This corresponded to a ∼6-fold rise in AMP/ATP in α1α2lox/lox + Albcre. Consistent with the effects on adenine nucleotides, maximal mitochondrial respiration was ∼30% lower in α1α2lox/lox + Albcre than α1α2lox/lox livers. Mitochondrial oxidative phosphorylation efficiency was reduced by 25%. In summary, these results demonstrate that the NMP capacity to inhibit glucose production in vivo is independent of liver AMPK. In contrast, AMPK promotes mitochondrial function and protects against a more precipitous fall in ATP during AICAR administration.

Original languageEnglish (US)
Pages (from-to)5950-5959
Number of pages10
JournalJournal of Biological Chemistry
Volume289
Issue number9
DOIs
StatePublished - Feb 28 2014

    Fingerprint

Cite this