Abnormal breakdown of adenosine diphosphate in uraemic plasma and its possible relationship to defective platelet aggregation

Abstract

Radioactive adenosine diphosphate (ADP-8- 14C) and adenosine triphosphate (ATP-8- 14C) were incubated with normal and uraemic plasma and their derivatives were detected and quantitated by thin-layer radiochromatography. In both normal and uraemic plasma ADP was broken down to AMP, adenosine and inosine but the presence of platelets had a retarding effect. ADP breakdown was impaired in uraemic plasma. In normal platelet-rich plasma the amount of adenosine formed correlated with the amount of ADP degraded but this relationship did not hold in renal failure possibly due to increased platelet adenosine uptake. The defective ADP breakdown in uraemic plasma was not related to the biochemical changes which occurred or to the degree of impairment of platelet aggregation. The results indicated that impaired plasma catabolism of ADP was associated with, but did not necessarily cause, defective platelet aggregation in chronic renal failure.