Further observations on the utilization of adenosine triphosphate in rat mast cells during histamine release induced by the ionophore A23187.

1 The relation between A23187-induced histamine release and the energy metabolism of the rat mast cells has been studied. 2 Ethacrynic acid was used as an inhibitor of calcium-induced histamine release from mast cells primed with the ionophore A23187, and to study calcium-induced changes in the adenosine triphosphate (ATP) content and the rate of lactate production of A23187-primed mast cells. 3 Ethacrynic acid by itself decreased the rate of glycolytic ATP production. 4 By measurement of the ATP content and the lactate production of mast cells with or without secretory activity, the increased demand of energy for exocytosis was estimated to be equivalent to 0.14 pmol of ATP pr 10(3) mast cells.