The cellular localization of a dopamine- and adenosine-3',5'-monophosphate (cAMP)-regulated phosphoprotein of an apparent molecular weight of 32,000 (DARPP-32) was investigated in mouse, rat, rabbit, guinea pig, cat, monkey (Macaca fascicularis and Marmoset) and human adrenal gland by means of indirect immunofluorescence histochemistry. DARPP-32-like immunoreactivity (-LI) was demonstrated in chromaffin cells in the adrenal medulla of rabbit, guinea-pig, cat, monkey and human, but not in mouse or rat. In the Marmoset monkey, DARPP-32-LI was also observed in the zona glomerulosa of the adrenal cortex. It has been shown that dopamine and dopaminergic agonists inhibit catecholamine release from chromaffin cells and aldosterone secretion from cells in the adrenal cortex. The present results suggest that DARPP-32, an intracellular third messenger for dopamine, may be part of the signal transduction mechanism for dopamine acting on the adrenal gland.