Aggregation of rat neutrophils by nucleotide triphosphates.

1 Adenosine 5'-triphosphate (ATP) and uridine 5'-triphosphate (UTP) at concentrations of 3 x 10(-7)M and greater cause a rapid partially reversible aggregation of rat polymorphonuclear leucocytes. 2 Other nucleotide phosphates are much less active at producing aggregation responses; the agonist potencies being UTP greater than ATP greater than guanosine 5'-triphosphate, cytidine 5'-triphosphate, thymidine 5'-triphosphate; ATP greater than adenosine 5'-diphosphate (ADP) greater than adenosine 5'-monophosphate (AMP); and ADP greater than uridine 5'-diphosphate, thymidine 5'-diphosphate, guanosine 5'-diphosphate, cytidine 5'-diphosphate. Adenosine is inactive. 3 The hydrolysis resistant analogues of ATP, alpha-beta-methylene ATP and beta-gamma-methylene ATP, do not cause neutrophil aggregation suggesting that hydrolysis of ATP and UTP may be required to initiate the aggregation response. 4 It is postulated that ATP and UTP may be important stimulants of neutrophil function and may be involved in the adherence of these cells to the vascular endothelium.