FIGURE 4.

Glutamine-induced IGF2 secretion requires glutamine metabolism but not mTOR activation. MIN6 cells were incubated for 3 h in the presence of the indicated concentrations of glucose and glutamine, and in presence of the glutaminase inhibitor DON or of rapamycin. A, glutamine-induced IGF2 secretion is dose-dependently inhibited by DON. B, rapamycin did not impact glutamine-induced IGF2 secretion. C, Western blot detection of phospho-4E-BP1 in the presence of glucose (mm), glutamine (2 mm), and rapamycin (100 nm). The data are the means ± S.D. from three independent experiments. *, p < 0.05; **, p < 0.01; ***, p < 0.001. DMSO, dimethyl sulfoxide.