Vasopressin release from rat medial basal hypothalamus induced in vitro by angiotensin

Rat medial basal hypothalami were superfused in vitro. The effect of angiotensin II on vasopressin outflow was investigated. Angiotensin II (10 nM or 1 μM, added to the superfusion medium) increased the veratridine-evoked vasopressin release. The higher concentration also slightly elevated the basal outflow. The effect of angiotensin II was blocked by saralasin. We conclude that angiotensin II can act on the median eminence and/or on the stump of the pituitary stalk to promote the release of vasopressin, which then may influence anterior pituitary hormone secretion.