Abstract
Transforming growth factor-beta 1 (TGF-beta 1) is a multifunctional polypeptide that regulates the proliferation and differentiation of various types of animal cells. TGF-beta 1 stimulated glucose uptake and the expression of a brain-type glucose transporter (GLUT1) mRNA in quiescent mouse 3T3 cells. TGF-beta 1 also synergistically stimulated these activities when given together with calf serum, phorbol ester, fibroblast growth factor, or epidermal growth factor. The increases in glucose uptake and the GLUT1 mRNA level were induced by picomolar concentrations of TGF-beta 1 within 3 h of stimulation, reached a peak between 6 and 9 h, and then decreased gradually to basal levels before an increase in DNA synthesis. The stimulation of GLUT1 mRNA expression was completely abolished by actinomycin D, but was not affected by cycloheximide, suggesting that new protein synthesis was not required for the expression of GLUT1 mRNA. TGF-beta 1 had little mitogenic activity and did not affect serum-induced DNA synthesis in quiescent 3T3 cells. However, it stimulated DNA synthesis synergistically when given with fibroblast growth factor, epidermal growth factor, phorbol ester, or insulin. These results suggest that TGF-beta 1 mediates the stimulation of glucose uptake, GLUT1 mRNA expression, and DNA synthesis via a pathway(s) and cellular components distinct from those for other growth factors. The possible role of the TGF-beta 1-induced stimulation of glucose transport activity in the control of mouse fibroblast proliferation is also discussed.
Highlights
TGF-Dl stimulated glucose uptake and the expression blasts in soft agamr edium
In addition to its effects on lated DNA synthesis synergistically when given with growth regulatorygenes, the stimulationof glucose transport fibroblastgrowthfactor,epidermalgrowthfactor, and glycolysis have been previously reported in fibroblasts phorbol ester, or insulin
Transforming growth factor-81 (TGF-81) mediates the stimulation of glucose uptake, Elevation of facilitated glucose transport is a well estab
Summary
TGF-Dl stimulated glucose uptake and the expression blasts in soft agamr edium. More recently, TGF-Bl was found of a brain-type glucose transporter (GLUTl)mRNA in to inhibit thgerowth of some cells,such as epitheliaclells and quiescent mouse 3T3 cells. Assaying of DNA Synthesis-Quiescent 3T3 cells in 35-mm culture dishes were incubated with the indicated growth factors or calf serum a t 37 "C in 1 ml of DMEM containing [3H]thymidine (0.2 pCi/ml, 1 p M ) for 24 h, and the intracellular level of 5% trichloroacetic acid-insoluble radioactivity was determined, as described previously
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