Impaired L-arginine uptake in platelets from type-2 diabetic patients.
The L-arginine uptake of resting platelets from type-2 diabetic patients and control subjects was measured and the kinetic parameters defined. The effect of platelet stimulation with agonists was also investigated. Kinetic studies showed that the K(m) value for L-arginine transport was not different in patients compared with control subjects, while V(max) was significantly decreased in patients compared with controls. Moreover, agonists able to mobilize Ca(2+) produced a further decrease in the L-arginine uptake in controls and in patients, suggesting that Ca(2+) intracellular levels down-regulate L-arginine transport in platelets from both control subjects and patients. Data suggest that drugs designed to control intracellular Ca(2+) might restore platelet function in diabetic patients.
Signorello
M G
MG
Department of Experimental Medicine, Biochemistry Section, University of Genoa, Viale Benedetto XV 1, 16132 Genova, Italy.
Giovine
M
M
Pascale
R
R
Cataldi
L
L
Bordone
C
C
Benatti
U
U
Leoncini
G
G
D000368:Aged; D001120:Arginine / Q000493:pharmacokinetics*; D001792:Blood Platelets / Q000378:metabolism*; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism; D013997:Time Factors
D009569:Nitric Oxide; D000001:Calcimycin; D001120:Arginine; D002118:Calcium