The relationship between changes in lipid fuel availability and tissue fructose 2,6-bisphosphate concentrations and pyruvate dehydrogenase complex activities in the fed state.

An elevated concentration of non-esterified fatty acids in the fed state elicited inhibition of cardiac, but not hepatic, pyruvate dehydrogenase complex (PDH). There was a modest decline in fructose 2,6-bisphosphate (Fru-2,6-P2) concentration in heart, and, to a lesser extent, in liver. Surgical stress decreased PDH activities and Fru-2,6-P2 concentrations in both heart and liver. Only the former response was abolished if postoperative lipolysis was inhibited. Surgery also decreased the [Fru-2,6-P2] in gastrocnemius: this response was abolished if lipolysis was inhibited.