The effects of insulin and spermine to stimulate glucose transport and glucose oxidation were measured. When the insulin - glucose transport and insulin - glucose oxidation dose response curves were compared, it was found that insulin increased oxidation to a greater extent than transport, and that half-maximal effects were reached at lower insulin concentrations for transport than for oxidation (0.15 ± .06 vs 0.5 ± 1 ng/ml, p < .01). This indicates that all of insulin's effects to increase glucose oxidation are not mediated through simple stimulation of glucose transport. Spermine's ability to promote adipocyte glucose metabolism was analogous to that of insulin, while hyperosmolarity (0.3 M sucrose) stimulated transport and oxidation equally. In the presence of cytochalasin B (which inhibits the ability of insulin, spermine, and hyperosmolarity to increase glucose transport) insulin and spermine could still increase the rate of glucose oxidation whereas hyperosmolarity could not. These results indicate that unlike 0.3 M sucrose, insulin and spermine can promote glucose oxidation independent of their effects to stimulate glucose transport. © 1976.
Olefsky, J. M. (1976). Insulin’s effect on glucose oxidation independent of glucose transport. Biochemical and Biophysical Research Communications, 71(1), 106–113. https://doi.org/10.1016/0006-291X(76)90255-2