Pyruvate dehydrogenase activation in inactive muscle during and after maximal exercise in men

Pyruvate dehydrogenase activity (PDHa) and acetyl-group accumulation were e xamined in the inactive deltoid muscle in response to maximal leg exercise in men, Seven subjects completed three consecutive 30-s bouts of maximal is okinetic cycling, with 4-min rest intervals between bouts. Biopsies of the deltoid were obtained before exercise, after bouts I and 3, and after 15 mi n of rest recovery. Inactive muscle lactate (LA) and pyruvate (PYR) content s increased more than twofold (P < 0.05) after exercise (bout 3) and remain ed elevated after 15 min of recovery (P < 0.05). Increased PYR accumulation secondary to LA uptake by the inactive deltoid was associated with greater PDHa, which progressively increased from 0.71 +/- 0.23 mmol min(-1) kg wet wt(-1) at rest to a maximum of 1.83 +/- 0.30 mmol min(-1) kg wet wt(-1) af ter bout 3 (P < 0.05) and remained elevated after 15 min of recovery (1.63 +/- 0.24 mmol min(-1) kg wet wt(-1); P < 0.05). Acetyl-CoA and acetylcarnit ine accumulations were unaltered. Increased PDHa allowed and did not Limit the oxidation of LA and PYR in inactive human skeletal muscle after maximal exercise.