There are contradictory reports about the relation between pituitary local renin-angiotensin system (RAS) and the secretory functions of lactotrophs. We evaluated the effect of the ACE inhibitor captopril on plasma prolaction, growth hormone and TSH secretion in patients with idiopathic hyperprolactinemia (n= 18) and in hypertensive patients with normal pituitaries (n=12). A slight but significant fall in plasma prolaction levels at 60 (p