Pyruvate Dehydrogenase Activation in Adipocyte Mitochondria by an Insulin-Generated Mediator from Muscle

Abstract

Material in a chromatographic fraction from an extract of insulin-treated muscle stimulated pyruvate dehydrogenase activity in addipocyte mitochondria. This action was similar to insulin's activation of the enzyme in a plasma membrane-mitochondria mixture. Neither the chromatographic fraction nor insulin required adenosine triphosphate or magnesium ion (Mg2+), suggesting that both agents acted through a calcium-sensitive phosphatase. This fraction may contain a chemical mediator of insulin action.