ABSTRACT
Human blood platelets are small, anucleated cells synthesized by megakaryocytes in the bone marrow. A better insight in the energy requirement of secretion responses was gained when it became possible to measure energy consumption in intact cells in extremely short-time intervals. Adenosine diphosphate (ADP) induces a biphasic pattern in the rate of energy consumption clearly illustrating the separate energy requirements of aggregation and secretion. The cells should maintain Adenosine triphosphate (ATP) homeostasis in order to be optimally responsive to a secretagogue. The fall in metabolic ATP is steeper with strong agonists, than with weak activators, indicating that the imbalance between supply and demand is greater as more secretion takes place. The gradual loss of dense granule ATP-ADP during prolonged storage of platelets for transfusion is also thought to result from a decrease in ATP resynthesizing sequences.
