Details

Autor(en) / Beteiligte

• CALDERHEAD, D. M
• KITAGAWA, K
• TANNER, L. I
• HOLMAN, G. D
• LIENHARD, G. E

Titel

Insulin regulation of the two glucose transporters in 3T3-L1 adipocytes

Ist Teil von

• The Journal of biological chemistry, 1990-08, Vol.265 (23), p.13800-13808

Ort / Verlag

Bethesda, MD: American Society for Biochemistry and Molecular Biology

Erscheinungsjahr

1990

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• The amounts of the brain type and muscle type glucose transporters (designated Glut 1 and 4, respectively) in 3T3-L1 adipocytes have been determined by quantitative immunoblotting with antibodies against their carboxyl-terminal peptides. There are about 950,000 and 280,000 copies of Glut 1 and 4, respectively, per cell. Insulin caused the translocation of both types of transporters from an intracellular location to the plasma membrane. The insulin-elicited increase in cell surface transporters was assessed by labeling the surface transporters with a newly developed, membrane-impermeant, photoaffinity labeling reagent for glucose transporters. The increases in Glut 1 and 4 averaged 6.5- and 17-fold, respectively, whereas there was a 21-fold in hexose transport. These results indicate that the translocation of Glut 4 could largely account for the insulin effect on transport rate, but only if the intrinsic activity of Glut 4 is much higher than that of Glut 1. The two transporters are colocalized intracellularly: vesicles (average diameter 72 nm) isolated from the intracellular membranes by immunoadsorption with antibodies against Glut 1 contained 95% of the Glut 4 and, conversely, vesicles isolated with antibodies against Glut 4 contained 85% of the Glut 1.