Fig. 1.

Free fatty acids and lipotoxic stress lead to sustained JNK activation. (A) Comparison of JNK activity using a solid-state kinase assay and GST-cJun (1–79) as a substrate in liver extracts from lean/nondiabetic, obese, and lean/diabetic mice. JNK1 levels were determined by immunoblotting. (B) JNK kinase activity in lysates of primary hepatocytes treated for the indicated times with delipidated BSA or BSA loaded with the indicated unsaturated (Left) or saturated (Right) fatty acids. (C) JNK activity in livers of mice that were perfused for 1 h with either delipidated or PA-loaded BSA.