Vasopressin (Antidiuretic hormone or ADH) is synthesised by the hypothalamus but is stored and released by the posterior pituitary (neurohypophysis). Its function is to act mainly at the kidney and stimulate resorption of water and electrolytes by the distal tubules , . Glucagon is secreted by the $\alpha$-cells (\alpha cells) of the Islets of Langerhans, not beta-cells (which secrete insulin) . Prolactin is secreted by the anterior pituitary (pars distalis), not the posterior pituitary .