Gastric bypass anatomy leads to diabetes control

NEW YORK (Reuters Health) - The rapid and substantial control of diabetes seen after gastric bypass surgery is due, at least in part, to the intestinal rearrangement involved in the procedure, the results of an animal study suggest.

Besides removing a substantial portion of the stomach, gastric bypass also attaches the output of the stomach to the lower intestines. The lower portion of the gut usually produces little glucose, but because of the direct input from the stomach it increases its production, French researchers report in the research journal Cell Metabolism.

The liver senses the higher level of glucose and reduces its own production of the sugar. Since the liver contributes much more to the body's overall glucose production than do the intestines, the net effect is enhanced glucose control, say Dr. Gilles Mithieux, from Universite de Lyon, and colleagues.

The increase in intestinal glucose formation was only noted with gastric bypass, not with gastric banding, which doesn't re-route the intestines. This may explain why only gastric bypass has been associated with enhanced diabetes control, the investigators conclude.

Furthermore, they note, sensors in the liver detect the elevated glucose and send an appetite-suppressing signal to the brain, which contributes to the satiety and weight loss seen with gastric bypass.

SOURCE: Cell Metabolism, September 3, 2008.