The effect of ouabain on the secretion of catecholamines and on the intracellular concentration of potassium.

1. Perfusion of bovine adrenal glands with 0.1 mM ouabain is accompanied by a doubling of the spontaneous rate of release of catecholamines and by a 66% increase in the response to stimulation with carbamylcholine.2. Perfusion with ouabain (0.1 mM) reduces the intracellular content of potassium from 106 to 63 mM.3. The effect of ouabain on catecholamine secretion is dependent upon the presence of Ca(2+) ions in contrast to the effect upon the potassium content which is not dependent upon the presence of calcium.4. Ouabain has no effect on the release of catecholamines from isolated chromaffin granules both in the presence and absence of Ca(2+) ions.5. A possible relationship between the secretion of catecholamines and the concentration gradient of potassium across the cell membrane is discussed.