Glucose transport in isolated rat adipose cells.

Several different approaches to the measurement of hexose transport rates in isolated adipocytes from lean and obese rats have been utilized in the last six years. The uptake as a function of time of the non-metabolizable sugar 3-0-methylglucose is so fast that until recently no measurements of the 'true' transport rates (ie initial velocity of influx) could be made. Other nonmetabolizable sugars such as L-arabinose are taken up more slowly, due to their low affinities and their influxes at early times are measureable. Alternatively, the uptake with time of 2-deoxyglucose, an analogue of glucose which is transported and phosphorylated, but not further metabolized, has been used extensively as a measure of transport rate. The data from different studies comparing the transport rates in adipocytes from lean and obese rats are at variance. The present discussion is an attempt to explain why the results of such studies have not always agreed. In addition, as a result of our recent studies comparing 2-deoxyglucose and 3-0-methylglucose transport, we introduce a new model of hexose transport in adipocytes.