Gastrin secretion after weight loss by dieting and intestinal bypass surgery

Abstract

Basal and stimulated gastrin levels were measured in 15 massively obese patients before and after weight loss from intestinal bypass surgery. Eight of these subjects were also studied after comparable weight loss on a diet that preceded the bypass surgery. Three lean subjects were studied as controls. Basal gastrin levels were similar in the lean subjects and in the obese subjects before bypass. There was no significant change in basal gastrin with weight loss by dieting, but there was a significant increase (P < 0.01) after intestinal bypass. Gastrin secretion was stimulated by a constant infusion of epinephrine (6 μg/min) for 60 min. There was no significant difference in gastrin levels in the lean subjects and in the obese subjects before bypass or after weight loss by dieting. After intestinal bypass gastrin secretion increased (P < 0.01) with epinephrine infusion. Gastrin secretion was also stimulated by a standard meal of an egg, toast with butter, and orange juice. Gastrin secretion was increased after bypass (P < 0.01), but there was no significant difference between lean subjects and obese patients before bypass. We conclude that basal and stimulated gastrin secretion are increased after weight loss from intestinal bypass but not after weight loss by dieting. The increase in gastrin secretion in fasting subjects during epinephrine infusion suggests that there may be an increase in gastrin-secreting cell mass after intestinal bypass.