A stimulatory effect of glutamine on glycogen accumulation in human
skeletal muscle.
Varnier, Maurizio, Graham P Leese, James Thompson, and Michael J
Rennie.
Department of Anatomy & Physiology, University of Dundee, Dundee
DD1 4HN, Scotland
APStracts 2:0075E, 1995.
To determine whether glutamine can stimulate human muscle glycogen
synthesis we studied the effect of infusion after exercise, of
glutamine, alanine-plus-glycine or saline in groups of 6 subjects.
The subjects cycled for 90 min at 70-140% O2max to deplete muscle
glycogen; afterwards, primed, constant-infusions of glutamine (30 mg
_ kg-1; 50 mg _ kg-1 _ hr-1) or an isonitrogenous, isoenergetic
mixture of alanine-plus-glycine or NaCl (0.9%) were administered.
Muscle glutamine remained constant during saline infusion, decreased
18% during alanine-plus-glycine infusion (P<0.001), but rose 16%
during glutamine infusion (P<0.001). By 2 h after exercise, muscle
glycogen concentration had increased more in the glutamine infused
group than in the saline or alanine + glycine controls (+2.8 +/- 0.6,
+0.8 +/- 0.4 and +0.9 +/- 0.4 [mu]mol g-1 wet weight respectively,
P<0.05 glutamine vs saline or alanine + glycine). Labelling of
glycogen by tracer U-[13C]glucose was similar in glutamine and saline
groups suggesting no effect of glutamine on the fractional rate of
blood glucose incorporation into glycogen. The results suggest that
after exercise, increased availability of glutamine promotes muscle
glycogen accumulation, by mechanisms possibly including diversion of
glutamine carbon to glycogen.
Received 16 May 1994; accepted in final form 4 April 1995.
APS Manuscript Number E182-4.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 April 1995.