Effect of different concentrations of 20HE on basal and AMP-stimulated activity of the AMP-activated protein kinase (AMPK)α1 catalytic subunit in H4IIE rat hepatoma cells. Cells were incubated with 0.1% DMSO (vehicle) and 2.5, 10, and 50 μM 20HE. The percentage of increase of AMPKα1 activation was 4, 14, and 32% for 2.5, 10, and 50 μM 20HE, respectively. Data represent the mean of 3 experiments ± SE. *P < 0.05, **P < 0.01. Student's t-test comparison for 20HE treatments vs. control.