ACTION OF INSULIN ON THE MOTILITY OF THE GASTROINTESTINAL TRACT

Abstract

Insulin has been found to increase the motility of the empty stomach and of the small intestine and colon; this action is related to the development of hypo-glycemia. A study of gastro-intestinal motility, there-fore, offers an excellent method for investigating the antagonism between insulin and pituitary extract or its fractions. The balloon technique was used to follow the hyperactivity of the gut produced by insulin administration and to determine the antagonistic action of pituitary extracts. The pituitrin preparations were usually administered intravenously but intramuscular injections were found to yield similar results: 74 experiments which gave definite results were performed and 11 dogs were used. Pituitrin, vasopressin, oxytocin, yasopressin-oxytocin and infundin were all found to inhibit high or low spontaneous motility of the stomach, small intestine and colon. They likewise inhibit the hypermotile gut of insulinized animals. The inhibition begins in 15-20 sec. (before the blood sugar Level is modified) acting probably through a direct paralysis of the motor mechanism of the gut. Modifications in carbohydrate metabolism are involved apparently in the later phase of the inhibition.