Angiotensin II (All) is present in gonadotropes in rats, and there are All receptors on lactotropes and corticotropes. All may be a paracrine mediator that stimulates the secretion of prolactin and adrenocorticotropin (ACTH) at the level of the pituitary, but additional research is needed to define its exact role. Angiotensinogen may also reach the gonadotropes via a paracrine route. On the other hand, there is considerable evidence that brain All stimulates the secretion of luteinizing hormone (LH) by increasing the secretion of LH-releasing hormone, and that this effect is due to All-mediated release of norepinephrine from noradrenergic nerve terminals in the preoptic region of the hypothalamus. In addition, brain All inhibits the secretion of prolactin, probably by increasing the release of dopamine into the portal hypophyseal vessels. Circulating All stimulates the secretion of a third anterior pituitary hormone, ACTH, by acting on one or more of the circumventricular organs to increase the secretion of corticotropin-releasing hormone.