Effect of fasting on myocardial glucose uptake in rabbits

ABSTRACT

In the present study, the effect of fasting on myocardial glucose uptake was studied. Two different techniques were used, namely cardiac muscle slices [0.5 mm thick] and the isolated heart perfusion using Langendorff's coronary technique. The effect of fasting for 1, 2, 3 and 4 days on glucose uptake was studied in both groups of experiments and the results were compared with control fed animals. The present results showed that in both groups of experiments [slices and isolated heart perfusion], fasting caused a significant increase in glucose uptake, an effect which was potentiated by increasing the duration of fasting. These results differed from previous studies which reported decreased glucose uptake by starvation. This difference could be explained by the difference in the substrate used, since previous studies used glucose and free fatty acids in the used solution or injected radioactive glucose in vivo then measured radioactivity after killing the animals, while in the present study glucose only was used as a substrate. The increase in glucose uptake could, also, be explained by its use for glycogen synthesis in cardiac muscle