PERFUSED RAT HINDLIMB IS SUITABLE FOR SKELETAL-MUSCLE GLUCOSE-TRANSPORT MEASUREMENTS

It has been postulated that the perfused rat hindlimb is unsuitable fo r measurements of muscle glucose transport [P. Hansen, E. Gulve, J. Ga o, J. Schluter, M. Mueckler, and J. Holloszy. Am. J. Physiol. 268 (Cel l Physiol. 37): C30-C35, 1995]. The aim of the present study was there fore to critically evaluate the suitability of this preparation for gl ucose transport measurements using the extracellular marker mannitol a nd the glucose analogs 3-O-methyl-D-glucose or 2-deoxy-D-glucose. In a ll three muscle fiber types studied, the rate of 2-deoxy-D-glucose upt ake during perfusion was linear from 1 to 40 min during maximal insuli n stimulation and from 1 to 15 min during maximal electrical stimulati on. Uptake of 2-deoxy-D-glucose was not increased by an increase in pe rfusate flow. Combined stimulation with a maximal insulin concentratio n and electrical stimulation elicited additive effects on 2-deoxy-D-gl ucose 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-deox y-D-glucose because of rapidly developing nonlinearity of accumulation . Our findings clearly demonstrate that the perfused hindlimb is suita ble for measurements of muscle glucose transport and that the most fea sible glucose analog for this purpose is 2-deoxy-D-glucose.