The pyruvate dehydrogenase complex during aging.

Acetylcholine synthesis and pyruvate oxidation decline with age. To determine the role of the pyruvate dehydrogenase complex in these age-related deficits, its activity and activation state were measured in vivo and in vitro in the brains of 3-, 10- and 30-month-old mice. Aging did not alter the active form of pyruvate dehydrogenase complex in vivo, although the total complex was 17% lower at 30 than at 3 months of age. In vitro, total or active forms of pyruvate dehydrogenase complex did not change with age. The results suggest that neither changes in total activity nor in the activation state of the pyruvate dehydrogenase complex account for the age-related deficits in oxidative or acetylcholine metabolism.