Influence of bradykinin on glucose uptake and metabolism studied in isolated cardiac myocytes and isolated perfused rat hearts.

To study whether bradykinin influences myocardial glucose metabolism as suggested for skeletal muscle, we studied the effect of bradykinin on myocardial glucose transport using isolated cardiac cells and on glucose metabolism using the isolated perfused rat heart. In isolated cardiac myocytes bradykinin alone had no influence on the initial velocity of basal glucose transport nor on the sensitivity of the glucose carrier towards stimulation by insulin. By contrast, in isolated perfused hearts bradykinin increased the rate of glucose uptake and oxidation as well as the formation of lactate independently of the action of insulin. In diabetic hearts, neither bradykinin nor insulin alone had a significant influence on myocardial glucose oxidation, however, both hormones together act synergistically to improve glucose oxidation. These data suggest that bradykinin enhanced the nutritional flow across the capillary wall and, thereby, indirectly accelerates the glucose metabolism in the isolated perfused heart. There is no evidence for a direct effect of bradykinin on the rate of glucose transport in the heart.