Endocrine Abstracts

Background

Appetite is complex, however to address the obesity epidemic, therapeutic agents would have to significantly influence appetite. Currently the most effective treatment for obesity is bariatric surgery because it reduces hunger and increases satiety. The satiety gut hormones such as peptide YY (PYY) and glucagon like peptide 1 (GLP-1) reduce appetite and food intake. Compared to lean and obese subjects, exaggerated postprandial responses of PYY and GLP-1 have been shown after gastric bypass but not gastric banding operations.

Aim

We evaluated the effect of physiological blockade of endogenously raised gut hormones in gastric bypass patients.

Method

A double blind randomised saline controlled trial recruited six gastric banding and five gastric bypass patients. They received either 100 microg in 1 mL of octreotide or 1 mL of 0.9% saline subcutaneously. One hour later they were given a standard ad libitum semi liquid meal. Blood was obtained every 30 minutes and gut hormones measured.

Results

Food intake was similar between gastric bypass (350±49 kcal) and gastric banding (441±197 kcal) patients on the saline day (P=0.7), but yet gastric bypass patients had exaggerated postprandial PYY and GLP-1 responses compared to gastric banding patients (P=0.03). Somatostatin blocked the endogenous gut hormone responses in both groups. Between the saline and octreotide days, the gastric banding patients showed no change in their food intake (P=0.2). However the gastric bypass patients increased their food intake by 87% from 350±49 kcal to 655±175 kcal (P=0.03).

Conclusion

Endogenous gut hormone responses are exaggerated in gastric bypass, but not gastric banding patients. Somatostatin physiologically blocks gut hormone responses. In gastric bypass, but not in gastric banding patients, suppression of gut hormones lead to increased food intake. Gut hormones thus appear to play an important role in food intake and may be a potential future treatment for obesity.