Serotonin uptake and glycolytic activity of human platelets after prolonged incubation with glucose-poor plasma

It is confirmed that metabolic energy is a prerequisite for the uptake of serotonin by human blood platelets. Starvation (i.e. incubation at 25 degrees C of platelets resuspended in glucose-poor autologous plasma) generally stops glucose consumption, lactate formation as well as serotonin uptake within 2 h. The addition of glucose restores lactate formation immediately and, independent of total starvation time, to normal or even higher levels. The active uptake of serotonin, however, can be restored only partly after prolonged incubation with glucose, to an extent which seems to be dependent of the preceding starvation time. The results are compatible with the hypothesis that besides an active carbohydrate metabolism another factor, presumably the integrity of the platelet membrane, is obligatory for the active transport of serotonin.