Blood-borne angiotensin II (AII) stimulates drinking, increases blood pressure and releases pituitary hormones (1), effects mediated, at least partial ly, through stimulation of AII receptors in circumventrjcular orEans (2). l.]e tried to determine whether AII could modulate the metabolic activity of its target sites in the rat brain, and whether any correlation could be found between such a modulation and the number of AII receptors in a particular brain structure.