Fatty acid efflux and triglyceride lipid label in cytokine treated THP-1 cells. Cells were differentiated for four days, then incubated for 24 h with [9,10(n)-3H]-oleate pre-incubated with lipoproteins (50 μg/ml) or added directly to cells (1 μCi/well). After removing non-attached lipids with a heparin rinse, cells were incubated in lipoprotein-free media for an additional 24 h with 0, 500, or 5000 pg/ml of respective cytokine. Cell lipids were extracted and lipid extracts separated by thin layer chromatography. Label was quantified in intracellular triglyceride fractions and conditioned media. A. Fatty acid label efflux normalized to intracellular triglyceride label in IL-1β treated cells, B. Fatty acid label efflux normalized to intracellular triglyceride label in TNF-α treated cells, C. Fatty acid label in intracellular triglyceride fractions from IL-1β treated cells, D. Fatty acid label in intracellular triglyceride fractions from TNF-α treated cells. Data represents mean ± SD (n = 6) for a representative experiment repeated three times. * = P < 0.05, ** = P < 0.01, *** = P < 0.001. Diamonds = control cells (no lipoprotein lipid loading), squares = AgLDL, triangles = VLDL.