Diabetes, Vol 48, Issue 2 327-333, Copyright © 1999 by American Diabetes Association
13C nuclear magnetic resonance study of glycogen resynthesis in muscle after glycogen-depleting exercise in healthy men receiving an infusion of lipid emulsion
MC Delmas-Beauvieux, B Quesson, E Thiaudiere, JL Gallis, P Canioni and H Gin
Resonance Magnetique des Systemes Biologiques, Unite Mixte de Recherche 5536, Centre National de la Recherche Scientifique-Universite Victor Segalen Bordeaux 2, France. cath@rmsb.u-bordeaux2.fr
In healthy individuals, glycogen recovery after a strong depletion is known
to be rapid and insulin independent during the initial phase, and
subsequently, slow and insulin dependent. Free fatty acids (FFAs) as a
putative source of insulin resistance (IR) could thus impair glycogen
recovery during the second period. Using in vivo 13C nuclear magnetic
resonance (NMR), we studied the effect of long-chain triglyceride emulsion
on gastrocnemius glycogen resynthesis during a 3-h recovery period after 90
min of moderate exercise consisting of plantar flexion on overnight-fasted
healthy men (n = 8). In separate experiments, each subject was infused with
10% Ivelip (0.015 ml x kg(-1) x min(-1)) or 10% glycerol (0.13 mg x kg(-1)
x min(-1)). NMR spectra were acquired before and at the end of the exercise
and during the recovery period. Whole-body glucose and lipid oxidation
rates (indirect calorimetry), plasma insulin, C-peptide, glucose, lactate,
beta-hydroxybutyrate, triglycerides, and FFAs were determined. Glycogen
consumption was 47.6 +/- 4.5% (glycerol) and 49.7 +/- 4.8% (Ivelip) of the
initial glycogen. An acquired IR in the Ivelip group was significant at the
onset of the recovery period by homeostasis model assessment (P = 0.002).
Glycogen resynthesis in the glycerol group appeared faster during the 1st h
than during the subsequent 2nd h of the postexercise period. The glycogen
resynthesis level was significantly lower in the Ivelip group than in the
glycerol group during the recovery period (P = 0.04 during the 1st h and P
= 0.001 during the next 2 h). During the recovery, plasma lactate and
whole-body oxidation rates were similar in the two groups, whereas glycemia
was significantly higher in the Ivelip group. A decreased cellular uptake
of glucose as a substrate for glycogenosynthesis, rather than a competition
between oxidation of carbohydrate and FFA, is discussed.