VIP: The Cause of the Watery Diarrhoea Syndrome

Abstract

Verner and Morrison in 1958 described a syndrome of refractory watery diarrhoea and hypokalaemia associated with non-insulin secreting tumours of the pancreatic islets. In the following years many such cases were reported and suggestions made as to the causative agent¹. In fact at one time or another almost all the characterised GI hormones have been put forward as the cause of the watery diarrhoea syndrome. In 1973 it was reported that the responsible tumour contained large quantities of the newly discovered polypeptide VIP and that plasma VIP levels were extremely elevated. The relationship of VIP to the syndrome seemed likely because the biological actions of VIP closely fitted the described symptoms of the patients. Thus, VIP is a potent stimulant of small intestinal juice production and a powerful inhibitor of gastric acid secretion. It also increases the output of hepatic glucose, stimulates pancreatic bicarbonate secretion, relaxes the gall bladder and causes vasodilation². These may explain the frequent clinical findings of hypochlorhydria, diabetes, flushing attacks, high resting pancreatic juice production and a flaccid distended gall bladder.