Decreased cellular energy levels are not responsible for activation of AMPK. A. Intracellular ATP levels, measured using a luminescence assay, are maintained in cells treated with t10,c12-CLA. TM4t cells were treated without or with 40 μM t10,c12-CLA for 24, 48, or 72 hr and cells harvested for measurement of ATP levels. Each bar represents the mean ± SEM of triplicate wells from a representative experiment. *, indicates a statistically significant difference compared to the control at the same time point. B. Attenuation of LKB1 expression by siRNA does not affect CLA-induced activation of AMPK. TM4t cells were transfected with LKB1 siRNA or control siRNA for 6 hr followed by treatment without or with 40 μM t10,c12-CLA for 24, 48 or 72 hr. Cells were harvested, and proteins evaluated by western blot.