Glycogen Synthesis in Human Gastrocnemius Muscle Is Not Representative of Whole-Body Muscle Glycogen Synthesis

Academic Medical Centre, Department of Endocrinology and Metabolism (F5-169), Meibergdreef 9, 1105AZ Amsterdam, The Netherlands.
Diabetes (Impact Factor: 8.1). 06/2005; 54(5):1277-82. DOI: 10.2337/diabetes.54.5.1277
Source: PubMed


The introduction of 13C magnetic resonance spectroscopy (MRS) has enabled noninvasive measurement of muscle glycogen synthesis in humans. Conclusions based on measurements by the MRS technique assume that glucose metabolism in gastrocnemius muscle is representative for all skeletal muscles and thus can be extrapolated to whole-body muscle glucose metabolism. An alternative method to assess whole-body muscle glycogen synthesis is the use of [3-(3)H]glucose. In the present study, we compared this method to the MRS technique, which is a well-validated technique for measuring muscle glycogen synthesis. Muscle glycogen synthesis was measured in the gastrocnemius muscle of six lean healthy subjects by MRS and by the isotope method during a hyperinsulinemic-euglycemic clamp. Mean muscle glycogen synthesis as measured by the isotope method was 115 +/- 26 micromol x kg(-1) muscle x min(-1) vs. 178 +/- 72 micromol x kg(-1) muscle x min(-1) (P = 0.03) measured by MRS. Glycogen synthesis rates measured by MRS exceeded 100% of glucose uptake in three of the six subjects. We conclude that glycogen synthesis rates measured in gastrocnemius muscle cannot be extrapolated to whole-body muscle glycogen synthesis.

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    • "This may have resulted in a glycogen synthesis rate before exercise with lower accuracy compared with that after the intervention. Nevertheless, in another study by our group without an exercise intervention (Serlie et al. 2005) this correction resulted in a very linear concentration increase of [1- 13 C]glycogen in muscle between 25 min (with rapid changing APE) and 120 min (with a more stable APE). Finally, the 13 C MRS measurements had to be performed in the early afternoon for logistic reasons. "
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