Fig. 5. (A) Time course of 2-deoxyglucose (2-DG) uptake in cod (Gadus morhua) ventricle strips incubated with 1 mmol l^-1 2-DG. Ventricle strips were incubated at 8°C for 60 min in medium containing 5 mmol l^-1 glucose, 35 mmol l^-1 mannitol and 0.1% bovine serum albumin (BSA). Strips were rinsed in glucose-free medium for 10 min and then incubated in medium containing 2 mmol l^-1 pyruvate, 1 mmol l^-1 2-deoxy-D-[³H(G)]glucose, 37 mmol l^-1 [U-¹⁴C]mannitol and 0.1% BSA to assay uptake for the indicated times. ICS indicates intracellular space. Values are means ± S.E.M. for six strips per point. (B) Relationship between 2-DG uptake and 2-deoxyglucose-6-phosphate (2-DG-6-P) accumulation in cod ventricle strips under basal conditions using 1 mmol l^-1 2-deoxy-D-[³H(G)]glucose. Strips were frozen after increasing periods of incubation (10–60 min) at 8°C. Intracellular 2-DG and 2-DG-6-P were measured after separation by ion-exchange chromatography into neutral and anionic fractions, respectively. The accumulation of 2-DG-6-P mirrored the rate of 2-DG uptake, whereas free 2-DG represented a minor component. The results are shown for 24 strips from six animals.