Stimulation of glucose uptake by transforming growth factor β: evidence for the requirement of epidermal growth factor-receptor activation

Transforming growth factor β (TGF-β), derived from human platelets, stimulates the uptake of 2-deoxyglucose by cultured cell monolayers 2- to 4-fold. Stimulation can be detected as early as 30 min with as little as 0.1 ng of TGF-β per ml and maximal effects can be obtained at 2 hr with 1 ng of the growth factor per ml. TGF-β-induced stimulation of sugar uptake is enhanced by the co-addition of platelet-derived growth factor (10 ng/ml) or epidermal growth factor (EGF, 1 ng/ml). The NR-6 variant of mouse 3T3 cells, which lack EGF receptors, is not stimulated by TGF-β. Antisera to EGF receptors that block 125I-labeled EGF binding also inhibit TGF-β stimulation of 2-deoxyglucose uptake, although 125I-labeled TGF-β binding remains unimpaired. In contrast, antisera to the EGF receptor, which do not block EGF binding, have no measurable effect on the TGF-β-stimulated uptake of 2-deoxyglucose. The authors confirm that the receptor for TGF-β is distinct from the receptor for EGF and the authors conclude that TGF-β stimulation of 2-deoxyglucose uptake requires the co-activation of the EGF receptor kinase system