Mitochondrial toxins inhibit IL-4-induced IGF-1 release. Microglial cells were treated with rotenone or 3-NP and stimulated with 10 ng/ml IL-4. After 24 hrs, IGF-1 was measured as described in Methods. Values are mean ± SEM for independent IGF-1 measurements. n = 14-16 wells (i.e., 7-8 separate experiments performed in duplicate); *= p < 0.05, **= p < 0.001, ***= p < 0.001, significantly different from corresponding basal (ANOVA followed by Bonferroni's Multiple Comparison test).