GLUTAMINE UTILIZATION IN RESTING AND STIMULATED PLATELETS

Exogenous glutamine was metabolized by platelets to glutamate, asparta te, and CO2; whereas no lactate was formed. The amount of aspartate an d CO2 produced from glutamine was reduced by the presence of glucose. On the other hand the rate of oxidation of glucose was reduced by the presence of glutamine. The potential energetic value of glutamine was lower than that of glucose, but the amino acid appeared to be a prefer ential respiratory substrate. The energy provision from glutamine also plays a role in the process of platelet activation, known to require an extra supply of ATP, since thrombin increased the rate of glutamine utilization in platelets. Upon cell activation an increase in asparta te and CO2 formation was observed and the stimulatory effect on glutam ine oxidation by thrombin was also maintained in the presence of gluco se.