Effect of streptozotocin-induced diabetes on the metabolism of ADP, AMP and adenosine in the pulmonary circulation of rat isolated lung.

The uptake and metabolism of radioactive ADP, AMP and adenosine was investigated in the pulmonary circulation of lungs taken from rats with streptozotocin-induced diabetes. Between 0.26 and 500 mumol/l ADP was extensively hydrolysed to AMP equally in control and diabetic lungs. At 1 mmol/l there was less ADP breakdown in diabetic lungs. Hydrolysis of AMP to adenosine was also less in diabetic lungs at 10 mumol/l and 1 mmol/l substrate concentration, but adenosine metabolism and uptake at these concentrations was not affected by diabetes. The results indicate that formation of the anti-aggregatory adenosine and, to a lesser extent, breakdown of the pro-aggregatory ADP were decreased in diabetic lungs and may contribute to the platelet hyperreactivity associated with diabetes.