Relationship between 201Tl uptake and oxidative metabolism in cultured myocardial cells

The uptake of thallium-201 (201Tl) by myocardial cells in cultures was assessed in the presence of 10(-3) M potassium cyanide (KCN), an inhibitor of mitochondrial respiration, and 10(-4) M dinitrophenol (DNP), an uncoupler of oxidative phosphorylation. The cultures were incubated with 14C-glucose or 14C-octanoate, allowing the measurement of the oxidative metabolism and beta-oxidation from the production of 14CO2. The results demonstrated a moderate decrease in the ratio between the intra/extracellular concentration of 201Tl (Tl i/e) in the presence of KCN (28.9 +/- 8.1 versus 35.6 +/- 9.7 in the controls, n.s.) and no change with DNP (37.6 +/- 9.7). Glycolysis and fatty acid oxidation were lowered with KCN (-28 +/- 15 and -45 +/- 22% respectively, p less than 0.05 in both cases) and were non significantly increased with DNP (+37 +/- 23 and +10 +/- 52% respectively). These results show that 201Tl intracellular uptake is not related directly, but is not totally independent of glycolysis and fatty acid oxidation.