Muscle glycogen synthesis in recovery from intense exercise in
man.
Bangsbo, J., K. Madsen, B. Kiens, E. A. Richter.
The August Krogh Institute, LHF, Universitetsparken 13, DK2D2100
Copenhagen, Denmark
APStracts 4:0088E, 1997.
The present study examined the role of lactate and glucose as
substrates for glyconeogenesis in muscle in recovery from high
intensity exercise in man. Seven subjects performed about 100 min of
intense intermittent one2Dlegged knee2Dextensor exercise on two
occasions; with (HL) and without (C) intense arm exercise between the
leg exercise bouts leading to end exercise arterial plasma lactate
concentrations of 16.0+/-1.6 and 9.2+/-1.6 mmol x l2D1, respectively
(p<0.05). At the end of exercise muscle lactate and glycogen was
similar in HL and C (20.5+/-1.3 vs. 17.3+/-2.0 mmol x kgD1 w.w. and
48.1+/-11.3 vs. 56.3+/-8.6 mmol x kg2D1 w.w., respectively). Muscle
glycogen increased (p<0.05) during the first 5 min of recovery only
in HL, but after 90 min of recovery the muscle glycogen concentration
was the same in C and HL (61.2+/-12.0 vs. 71.5+/-10.9 mmol kg2D1
w.w.). Muscle lactate not released to the blood could maximally
account for 28% (C) and 54% (HL) of the increase in muscle glycogen
during 902Dmin of recovery or less than 10% of glycogen synthesis
after full recovery. The total net glucose uptake corresponded to 84%
(C) and 57% (HL) of the glycogen synthesized. Apparently, muscle
glyconeogenesis may occur in man, but the role of lactate as a
substrate is minor. Instead, blood glucose appears to be the most
important precursor for muscle glycogen synthesis after intense
exercise.
Received 10 December 1996; accepted in final form 7 April 1997.
APS Manuscript Number E608-6.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 13 May 1997