Vol. 276, Issue 3, E483-E488, March 1999
Pyruvate dehydrogenase activation in inactive muscle during
and after maximal exercise in men
C. T.
Putman1,
M. P.
Matsos1,
E.
Hultman2,
N. L.
Jones1, and
G. J. F.
Heigenhauser1
1 Department of Medicine,
McMaster University Medical Centre, Hamilton, Ontario, Canada L8N
3Z5; and 2 Department of Clinical
Chemistry, Huddinge University Hospital, Karolinska Institute,
S-141 86 Huddinge, Sweden
Pyruvate dehydrogenase activity
(PDHa) and acetyl-group
accumulation were examined in the inactive deltoid muscle in response to maximal leg exercise in men. Seven subjects completed three consecutive 30-s bouts of maximal isokinetic cycling, with 4-min rest
intervals between bouts. Biopsies of the deltoid were obtained before
exercise, after bouts 1 and
3, and after 15 min of
rest recovery. Inactive muscle lactate (LA) and pyruvate (PYR) contents increased more than twofold (P < 0.05) after exercise (bout 3) and
remained 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 wt1 at rest to a
maximum of 1.83 ± 0.30 mmol · min1 · kg
wet wt1 after
bout 3 (P < 0.05) and remained elevated
after 15 min of recovery (1.63 ± 0.24 mmol · min1 · kg
wet wt1;
P < 0.05). Acetyl-CoA and
acetylcarnitine accumulations were unaltered. Increased
PDHa allowed and did not limit the
oxidation of LA and PYR in inactive human skeletal muscle after maximal exercise.
acetylcarnitine; acetyl-coenzyme A; lactate metabolism
