Bariatric Times - January 2009 - (Page 20)

20 Metabolic Perspective Bariatric Times • January 2009 The Mechanism of Type-2 Diabetic Surgery by Edward E. Mason, MD, PhD, FACS Continued from Page 1 THE MECHANISM The Gila monster kept the whole apparatus in the lower jaw. Vonk et al in the study of the evolution of snakes has shown how the back teeth moved around to form fangs in the front or back of the upper jaw in various snakes.1 Some of us have dealt with buried wisdom teeth in the lower jaw. They may be left over from the lizard’s glucose regulating apparatus. The Gila monster appeared 200 million years ago. Snakes appeared 120 million years ago. Mammals and humans, appearing much more recently, have continued use of the glucoseregulating hormone now known as GLP-1. In humans, the hormoneproducing cells moved to the ileum, but exposure to glucose and lipids early in a meal remains necessary for stimulating secretion. Obesity interferes with this exposure and results in an increased insulin requirement. Some of the evidence for all of this is as follows: Shortly after a high-glucose meal, in lean, healthy people there is a flush of the intestine that may encourage a trip to the bathroom, a “gastrocolic reflex.” According to Brener et al,2 the volume of stomach contents governs initial emptying. If the initial gush is large enough to overflow the duodenum and if the stomach contents are highly concentrated, the small bowel flushes the overflow to the ileum. Lcells in the ileum are stimulated by glucose and fat to secrete GLP-1.3,4 This process in lean people fails with increasing obesity.5 No gush, no flush. Deficient GLP-1 stimulation of insulin receptors causes susceptible people to develop type-2 diabetes (T2D). Both intestinal bypass and gastric bypass prevent and cure T2D by exposing the ileum to glucose and fat, which stimulate secretion of GLP-1. GLP-1 stimulates insulin receptors. After the initial gush, the duodenum controls subsequent squirts. The words gush and squirt are Brener’s, and apropos to explaining the control of GLP-1 secretion. When further ingestion increases the volume of stomach contents, a new “initial gush” occurs and another sample of gastric contents reaches the ileum. GLP-1 was first known as a brake hormone, which stops gastric emptying. The duodenal calorie counting, glucose receptors, and osmoreceptors resume regulation of subsequent stomach squirts to maintain the optimum rate of entry of calories into the duodenum. In 1945, I began surgical training at the University of Minnesota with

Table of Contents Feed for the Digital Edition of Bariatric Times - January 2009

Bariatric Times - January 2009 Surgical Perspective Psychological Perspective Metabolic Perspective Editorial Message Table of Contents Editorial Board Anesthesiology Perspective Body Contouring Perspective Journal Watch Advertiser Index News & Trends

Bariatric Times - January 2009

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.