Synergistic induction of IL-6 mRNA in primary human monocytes. Monocytes isolated by adherence from human PBMC fraction of whole blood were incubated for 30 minutes with varying concentrations of insulin, followed by 24 hour incubation with 500 μM palmitate or BSA. IL-6 (A) and TNF-α (B) mRNAs were determined by qRT-PCR. Values are means ± SE (n = 3) expressed relative to the expression level of these cytokines in BSA-treated cells. *, p < 0.05 versus (- insulin).