The enhanced renal response to aldosterone observed in rats on a high potassium diet is reduced by the administration of either haloperidol, a dopamine receptor blocker, or carbidopa, a peripheral blocker of dopa decarboxylase. This suggests that one peripheral action of dopamine is to modulate the action of aldosterone on the kidney. 2. No difference in urinary dopamine excretion after an 18 h fast was found in rats that had been either on a control diet or a high potassium diet. Both groups of rats responded by a similar elevation after an acute potassium load. This suggests that dopaminergic mediation of the enhanced response to aldosterone in rats on a chronic high potassium diet is not detectable by changes in urinary dopamine excretion.
