Inhibition of the Transport of Several Hexoses in Mammalian Cells by Cytochalasin B

Cytochalasin B inhibited the transport of several hexoses in HeLa, 3T3, HTC rat hepatoma, and chick embryo heart cells. Fifty per cent inhibition of [3H]glucose, [3H]glucosamine, and 2-deoxy[3H]glucose transport occurred with 8 x 10-8 m cytochalasin B. Inhibition of hexose transport was immediate and was immediately and completely reversible when cytochalasin B was removed from the medium after 1 hour of incubation. Cytochalasin B did not prevent the uptake of thymidine, uridine, α-aminoisobutyric acid, or calcium. Hexokinase activity of a HeLa cell sonicate was also unaffected by cytochalasin B. Inhibition of glucose transport appeared to be noncompetitive.