Effects of epinephrine and perfusion pressure on the peak aortic pressure development and glucose transport in the isolated perfused heart of normal and diabetic rats.

The effects of increased perfusion pressure and epinephrine stimulation on the contractile parameters and glucose transport in the isolated perfused hearts of control and ketotic diabetic rats were studied. An increase in perfusion pressure from 60 mm Hg to 100 mm Hg resulted in increases in coronary flow and peak aortic pressure development in control and diabetic hearts. The responses of the diabetic heart were similar to the control. Epinephrine produced lower increments in peak aortic pressure development in control and diabetic hearts under the higher perfusion pressure. Glucose uptake, although stimulated about 4-fold in both control and diabetic hearts on increasing the perfusion pressure, was still lower in the diabetic heart. Epinephrine stimulated glucose uptake in both control and diabetic hearts at 60 mm Hg, but the control heart showed a greater response. At 100 mm Hg perfusion pressure, the stimulatory effect of epinephrine on glucose uptake was abolished in both control and diabetic hearts. The results of this study show that the contractile and glucose stimulatory effects of epinephrine were influenced by the perfusion pressure. Epinephrine did not correct the impairment in glucose transport in the diabetic heart.