QUANTITATIVE METHODS FOR MEASURING THE INSULIN-REGULATABLE GLUCOSE-TRANSPORTER (GLUT4)

This review article describes various quantitation methods for the ins ulin-regulatable glucose transporter (Glut4). Several methods includin g reconstituted glucose transport, cytochalasin B binding assays, immu nocytochemistry, immunoblots, ELISA, and the more recently developed e xofacial labels are discussed. Since Glut4 translocates from an intrac ellular compartment to the plasma membrane in response to the action o f insulin, it is of particular interest to measure Glut4, changes in t he membrane fractions. Hence, the measurement of Glut4 commonly involv es the isolation of cell membranes using subcellular fractionation in combination with one of the quantitation methods. The limitations of e ach quantitation method due to the use of subcellular fractionation ar e discussed in this article. As well, the advantages and disadvantages in terms of isoform specificity and technical difficulties of each me thod are presented. (C) 1997 Elsevier Science Inc.