DIADENOSINE 5',5'''-P-1,P-4-TETRAPHOSPHATE (AP(4)A), ATP AND CATECHOLAMINE CONTENT IN BOVINE ADRENAL-MEDULLA, CHROMAFFIN GRANULES AND CHROMAFFIN CELLS

The level of diadenosine 5',5'''-P-1-P-4-tetraphosphate (diadenosine tetraphosphate or Ap(4)A), catecholamines, ATP and other nucleotides has been investigated in perchloric acid extracts of bovine adrenal medulla, chromaffin granules and cultured chromaffin cells. As a control, the amount of Ap(4)A and ATP has also been measured in human blood platelets. The following values (nmol/mg protein) were found in adrenal medulla: Ap(4)A, 0.019 +/- 0.004; ATP, 109 +/- 11; ADP, 23.8 +/- 5.8; AMP, 11.3 +/- 1.5; p(4)A, 0.18 +/- 0.08; catecholamines, 460 +/- 57. The level of Ap(4)A, catecholamines and ATP (nmol/mg protein) found in chromaffin granules and in chromaffin cells were, respectively: (0.15 +/- 0.07; 2175 +/- 99; 531 +/- 66) and (0.22 +/- 0.14; 1143 +/- 277; 222 +/- 53). In all the cases investigated, the ratio catecholamines/ATP and catecholamines/Ap(4)A were around 5 and in the order of 10(3), respectively. The amount of Ap(4)A found here, in bovine adrenal medulla, chromaffin granules and chromaffin cells, is two orders of magnitude lower than previously reported.