Da. Maclean et al., Determination of muscle-specific glucose flux using radioactive stereoisomers and microdialysis, AM J P-ENDO, 280(1), 2001, pp. E187-E192
Citations number
20
Categorie Soggetti
Endocrinology, Nutrition & Metabolism
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM
The purpose of the present study was to evaluate a novel approach for deter
mining skeletal muscle-specific glucose flux using radioactive stereoisomer
s and the microdialysis technique. Microdialysis probes were inserted into
the vastus lateralis muscle of human subjects and perfused (4 mul/min) with
a Ringer solution containing small amounts of radioactive D- and L-glucose
as the internal reference markers for determining probe recovery as well a
s varying concentrations of insulin (0-10 mM). The rationale behind this ap
proach was that both stereoisomers would be equally affected by the factors
that determine probe recovery, with the exception of L-glucose, which is n
onmetabolizable and would not be influenced by tissue uptake. Therefore, an
y differences in the probe recovery ratios between the D- and L-stereoisome
rs represent changes in skeletal muscle glucose uptake directly at the tiss
ue level. There were no differences in probe recovery between the D- (42.3
+/- 3.5%) and L- (41.2 +/- 3.5) stereoisomers during the control period (no
insulin), which resulted in a D/L ratio of 1.04 +/- 0.03. However, during
insulin perfusion (1 muM). The D/L ratio increased to 1.62 +/- 0.08 and 1.5
8 +/- 0.07 (P < 0.05) during the two collection (0-15 and 15-30 min) period
s, respectively. This was accomplished solely by an increase (P < 0.05) in
D- glucose probe recovery, as L- glucose probe recovery remained unchanged.
In a second set of experiments, the perfusion of 10 muM insulin did not in
crease the D/L ratio (1.40 +/- 0.11) above that observed during 1.0 muM (1.
41 +/- 0.07) insulin perfusion. These data suggest that this method is suff
iciently sensitive to detect differences in insulin-stimulated glucose upta
ke; thus the use of radioactive stereoisomers in conjunction with the micro
dialysis technique provides a novel and useful technique for determining ti
ssue-specific glucose flux and insulin sensitivity.