Fasting and postprandial serum gastrin levels in obese and slim subjects, and the effects of surgical treatment for obesity on serum gastrin levels.

23 obese and 17 control subjects were studied after ingestion of a heavy breakfast, and 11 obese and 11 control subjects were studied after ingestion of a mixed liquid test meal. Five subjects from the latter group were also studied two and six weeks after a jejuno-ileal bypass operation and the remaining six subjects from this group were studied twelve weeks after a stapled gastric partitioning. No significant differences in fasting or postprandial serum gastrin levels were found between the obese and the lean subjects, neither when studied with the breakfast meal nor when studied with the mixed liquid test meal. After the jejuno-ileal bypass operation the serum gastrin levels were not significantly different from the preoperative ones, whereas both the fasting and the postprandial serum gastrin levels were significantly augmented after the stapled gastric partitioning procedure. The group operated on with the latter method was also studied with an insulin test before and after the operation. Similar to that seen after ingestion of the mixed liquid test meal, the serum gastrin levels after the insulin-induced hypoglycemia were significantly higher postoperatively.