A peptide fragment of ACTH and an antagonist of MC2R inhibits ACTH-induced corticosterone production in isolated rat adrenal cells at 0.455 or 4.55 UM inhibits ACE1 (IC50 750 nM for the dog enzyme) inhibits basal cAMP secretion by isolated rat inner adrenocortical cells at 1 UM induces hypotension in normotensive dogs (ED50 0.109 nmol/kg)