The Release of Catechol Amines from the Amine Containing Granules of the Adrenal Medulla.

No or a very slow release of catechol amines occurs when the granules isolated from cow adrenal medulla are kept at 0° to +4°C. If the temperature is elevated, a liberation takes place both in sucrose and electrolytic media. No inhibitors for this “spontaneous” release have been found. The ATP stored in the granules decreases parallelly with the catechol amines. The ADP and AMP, however, do not drop in the same proportion. No or only small amounts of the soluble proteins in the granules are liberated during the amine release. The experiments speak against the view that the “spontaneous” amine release is brought forth by an ATP break-down. Instead it seems highly probable chat ATP is liberated along with the amines and then secondarily split into AMP and inorganic P by the combined activity of the ATPase and adenylate kinase of the medullary granules.