FIGURE 6.

Amino acid levels affect FFA-induced ROS generation and apoptosis in H4IIEC3 cells. Influence of amino acid availability on FFA-induced ROS generation (A) and also caspase-3/7 activity and DNA laddering (B). H4IIEC3 cells were incubated with 400 μm palmitate both with and without 50 μm oleate and under varying concentrations of amino acids (1.08, 2.15, or 8.6 mm). DCF fluorescence was determined after a 12-h incubation, whereas caspase-3/7 activity and DNA laddering were measured after a 24-h incubation. In the electrophoresis gel images (B, right panels), the label of each lane corresponds to the conditions in the bar graph of caspase-3/7 activity (B, left panels) except for the size marker (M). Amino acid concentrations are expressed as a magnification ratio in comparison with their physiological level (2.15 mm). Values are expressed as mean ± S.E. (n = 3). *, p < 0.05; **, p < 0.01 for the comparison with untreated cells (white bars) or as indicated.