The Streptozotocin-induced diabetic rat model of insulin-dependent diabetes mellitus is associated with a marked reduction in insulin's ability to stimulate glucose transport in the isolated rat adipose cell. Since insulin appears to enhance glucose transport by triggering a rapid and reversible translocation of glucose transport systems from a large intracellular pool to the plasma membrane, the effects of streptoxotocin-induced diabetes on this pool and the translocation process in the isolated adipose cell have been examined. With the induction of diabetes, insulin's ability to stimulate 3-0-methyglucose transport in intact cells and to increase the concentration of glucose transport systems in the plasma membrane fraction prepared from these cells is decreased by 55% and 40%, respectively. At the same time, the basal concentration of glucose transport systems in the low-density microsomal membrane fraction prepared from cells of the diabetic animals is decreased by 45%. Thus, the reduced glucose transport response of the adipose cell to insulin in the streptozotocin-induced diabetic rat appears to be the consequence of a relative depletion of glucose transport systems in the intracellular pool.