FIGURE 3.

Glutamine-induced IGF2 secretion is controlled at the translational level. MIN6 cells were treated as indicated in the presence of 2 or 20 mm glucose, 2 mm glutamine, and in the presence of cycloheximide (CHX) or actinomycin A. Intracellular and secreted IGF2 were then determined. A, the secretion of IGF2 stimulated by glutamine is suppressed in the presence of cycloheximide. B, the presence of cylcoheximide suppresses the intracellular levels of pro-IGF2 and mature IGF2 in glutamine-stimulated cells. C, actinomycin A did not significantly reduce glutamine-stimulated IGF2 secretion. D, the Igf2 mRNA levels were not reduced by actinomycin A in the experimental conditions used for these experiments. The data are the means ± S.D. from three independent experiments. *, p < 0.05; **, p < 0.01; ***, p < 0.001.