FIG. 9.

Amino acid sufficiency modulates insulin-stimulated GLUT4 translocation in 3T3-L1 adipocytes. 3T3-L1 adipocytes expressing the GLUT4 reporter were cultured in MEM with the indicated concentrations of amino acids for 36 h and serum starved during the last 12 h. Cells were stimulated with 160 nM insulin for the indicated times, then chilled, stained for externalized Myc epitope tag, and analyzed by flow cytometry to determine the relative proportion of GLUT4 at the cell surface in each sample. MEM with 2× amino acids approximates the amino acid concentrations found in DMEM (see Materials and Methods). Culture of the cells in media with poor amino acid availability results in reduced translocation of GLUT4 to the cell surface after insulin stimulation.