ADH/Vasopressin is stored in the posterior hypothalamus and is released into the blood stream when the effective osmotic pressure of plasma is increased above 285mOsm/kg. Its secretion is regulated by osmoreceptors located in the anterior hypothalamus. Vasopressin secretion is increased in: Increased effective osmotic pressure of plasma Decreased ECF volume Pain, emotion, stress, exercise Nausea and vomiting Standing Clofibrate, carbamazepine Angiotensin II Vasopressin Secretion Decreased Decreased effective osmotic pressure of plasma Increased ECF volume Alcohol Effects of vasopressin: It increases the permeability of the collecting ducts of the kidney so that water enters the hypeonic interstitium of the renal pyramids. V1A receptors mediate the vasoconstrictor effect of vasopressin and is potent stimulator of vascular smooth muscle. It cause glycogenolysis in the liver. V1B receptors in the anterior pituitary mediate increased secretion of ACTH from the coicotropes.