Expression and regulation by insulin of GLUT 3 in UMR 106-01, a clonal rat osteosarcoma cell line

Expression of the glucose transporter GLUT 3 is mainly restricted to neuronal tissues, with lower levels in testis and placenta. In addition, GLUT 3 has recently been reported in neonatal rat calvaria by in situ hybridisation. We report the co-expression of GLUT 1 and GLUT 3 mRNA and protein in UMR 106-01, a clonal osteosarcoma cell line. By semi-quantitative analysis we show that GLUT 3 protein is expressed at levels comparable to GLUT 1. Insulin stimulates glucose uptake in UMR 106-01 cells. GLUT 3 mRNA and protein are increased by chronic (16 h) treatment with insulin, and the increase in GLUT 3 mRNA is not inhibited by cycloheximide. Regulation of GLUT 3 mRNA by insulin has not been previously shown. UMR 106-01 represents a useful model for investigating regulation of GLUT 3 expression.