Regulation of pancreatic exocrine secretion is comprised of a complex interplay between hormonal and nervous mechanisms. Stimulatory gut hormones which act via the circulation include secretin, CCK, gastrin and bombesin, while VIP operates through peptidergic nervous release. Pancreatic polypeptide and glucagon are two examples of circulating inhibitory hormones while inhibition by somatostatin is through a paracrine release mechanism. Although the effects of vagal cholinergic nerves have been previously thought to be indirect through hormone release evidence is now accumulating for a direct role. Altered hormone release has been noted in chronic pancreatic insufficiency, cystic fibrosis and coeliac disease and may contribute in an important way to the pathophysiology of these malabsorptive disorders.