Synergistic induction of IL-6 by palmitate and insulin. A, IL-6 and TNF-α mRNA expression in THP-1 cells stimulated for 30 minutes with 5 ng/ml insulin (+ insulin) or vehicle (- insulin) and then stimulated with palmitate (250 μM) or fatty acid-free BSA, for an additional 12 hours. B, IL-6 and TNF-α concentration in media from THP-1 cells stimulated for 30 minutes with the indicated concentrations of insulin and then stimulated with palmitate (125 μM) for 24 hours. Values are means ± SE (n = 3). *, p < 0.05, #, p < 0.01 versus (- insulin).