Gastrin secretion before and after gastric bypass surgery for morbid obesity.

Fasting, meal-stimulated, and insulin-hypoglycemia-stimulated serum gastrin levels were measured before and 3 and 12 months after gastric bypass surgery in nine obese patients. The basal gastrin concentration was unaffected by the operation. After a meal both serum gastrin and blood glucose levels were significantly increased before the operation (p less than 0.002), whereas there was no significant gastrin release in response to food 3 and 12 months after the operation. Insulin hypoglycemia did not elicit any gastrin response either before or after gastric bypass surgery, even though considerable hypoglycemia was obtained. It is concluded that this lack of gastrin release after food and insulin hypoglycemia postoperatively may in part explain the rare development of peptic ulcer in patients after extensive gastric exclusion.