Impaired L-arginine uptake in platelets from type-2 diabetic patients

The L-arginine uptake of resting platelets from type-2 diabetic patients an d control subjects was measured and the kinetic parameters defined. The eff ect of platelet stimulation with agonists was also investigated. Kinetic st udies showed that the K-m value for L-arginine transport was not different in patients compared with control subjects, while V-max was significantly d ecreased in patients compared with controls. Moreover, agonists able to mob ilize Ca2+ produced a further decrease in the L-arginine uptake in controls and in patients, suggesting that Ca2+ intracellular levels down-regulate L -arginine transport in platelets from both control subjects and patients. D ata suggest that drugs designed to control intracellular Ca2+ might restore platelet function in diabetic patients.