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Diadenosine Tetraphosphate Is Co‐Released with ATP and Catecholamines from Bovine Adrenal Medulla

1992; Wiley; Volume: 59; Issue: 2 Linguagem: Inglês

10.1111/j.1471-4159.1992.tb09428.x

1471-4159

Carlos Castillo, Marı́a A. Moro, Mercedes del Valle, Antonio Sillero, Antonio G. Garcı́a, Marı́a A. Günther Sillero,

RNA regulation and disease

Abstract: Secretion of adenosine(5′)tetraphospho(5′)adenosine (Ap 4 A) and ATP from perfused bovine adrenal glands stimulated with acetylcholine or elevated potassium levels was measured and compared with that of catecholamines. We have found a close correlation between the release of Ap 4 A and catecholamines elicited with all the secretagogues used in the presence of either Ca 2+ or Ba 2+ , suggesting co‐release of both constituents from the chromaffin granules. By contrast, ATP secretion, as measured with luciferase, showed a significantly different time course regardless of the secretagogue used. ATP secretion consistently decreased after 1‐2 min of stimulation at a time when Ap4A and catecholamine secretions were still increasing. Measures of degradation of injected [ 3 H]ATP to the gland during stimulation showed little difference in the level of uptake or decomposition of ATP throughout the pulse. However, a reexamination of ATP secretion by monitoring its products of degradation (AMP, adenosine, and inosine) by HPLC techniques showed that Ap4A, ATP, and catecholamines are indeed secreted in parallel from the perfused adrenal gland.