Purine metabolites and malondialdehyde in platelets of diabetic patients

The concentration of some of the purine nucleotides and their metabolites t ogether with that of malondialdehyde (MDA) have been measured in resting an d stimulated platelets of type 1 and type 2 diabetic patients. While contro l platelets show a net decrease of guanosine triphosphate (GTP) (3.1 vs. 2. 3 nmol per 10(9) platelets) and guanosine diphosphate (GDP) (3.0 vs. 2.0 nm ol per 10(9) platelets) and a significant increase of adenosine (0.04 vs. 0 .55 nmol per 10(9) platelets) with platelet stimulation, platelets of type 1 and type 2 diabetic patients have a lesser change of these metabolites (G TP, 2.6 vs. 2.4; GDP, 2.3 vs. 2.4; adenosine, 0.04 vs. 0.30 (P < 0.05 vs. c ontrol) nmol per 10(9) platelets in type 1 diabetics; GTP, 2.4 vs. 2.7; GDP , 2.4 vs. 2.1; adenosine, 0.08 vs. 0.32 (P < 0.05 vs. control) nmol per 10( 9) platelets in type 2 diabetics). These results indicate that the change ( stimulated minus resting) of GTP, GDP and adenosine in diabetic platelets i s significantly different from that of controls (P < 0.001). Moreover, the amount of MDA produced during platelet activation seems to be lower than co ntrols only in type 2 diabetes (1.81 vs. 2.86 nmol per 10(9) platelets, P < 0.05). These results seem to indicate that a difference in the pattern of platelet nucleotides could be an important feature even in well-controlled diabetes, while MDA is probably modified only in association with the late vascular complications of diabetes. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.