Fig. 4. Adenosine phosphorylation is required for AMPK activation in IEC-6 cells. The effect of adenosine kinase inhibition on the increase in AMPK activity triggered by adenosine (Ado) was monitored after pre-incubating the cells with 0.2 µM 5'-iodotubercidin (5'-ITU) for 30 minutes. (A) Endogenous 1AMPK activity (mean ± s.e.m.) from four independent experiments. (B) Two representative western blots of phosphorylated AMPK (P-AMPK) and phosphorylated ACC (P-ACC), and corresponding densitometric analysis (means ± s.e.m.). (C) The effect of 5'-ITU on AICAR-triggered AMPK stimulation was determined. A representative western blot and corresponding densitometric analysis is shown. The statistical significance was assessed by Student's t-test: A: *P<0.05, **P<0.01; B: *P<0.05; C: **P<0.01. Ctrl or C, control.