RESUMO
It has been postulated that the perfused rat hindlimb is unsuitable for measurements of muscle glucose transport [P. Hansen, E. Gulve, J. Gao, J. Schluter, M. Mueckler, and J. Holloszy. Am. J. Physiol. 268 (Cell Physiol. 37): C30-C35, 1995]. The aim of the present study was therefore to critically evaluate the suitability of this preparation for glucose transport measurements using the extracellular marker mannitol and the glucose analogs 3-O-methyl-D-glucose or 2-deoxy-D-glucose. In all three muscle fiber types studied, the rate of 2-deoxy-D-glucose uptake during perfusion was linear from 1 to 40 min during maximal insulin stimulation and from 1 to 15 min during maximal electrical stimulation. Uptake of 2-deoxy-D-glucose was not increased by an increase in perfusate flow. Combined stimulation with a maximal insulin concentration and electrical stimulation elicited additive effects on 2-deoxy-D-glucose uptake in slow- and fast-twitch oxidative but not in fast-twitch glycolytic muscle fibers. Furthermore, in muscles having high glucose transport capacities 3-O-methyl-D-glucose is less suitable than 2-deoxy-D-glucose because of rapidly developing nonlinearity of accumulation. Our findings clearly demonstrate that the perfused hindlimb is suitable for measurements of muscle glucose transport and that the most feasible glucose analog for this purpose is 2-deoxy-D-glucose.