Endocrine Abstracts

Objective

Bariatric surgery has an important role in the management of morbidly obese patients. Roux-en-Y gastric bypass (RYGB) is an established bariatric procedure. In this study, we aimed to investigate prospective changes in the entero-hypothalamic endocrine axis following RYGB, examining the meal-stimulated responses of peptide-YY (PYY), glucagon-like peptide 1 (GLP-1) and ghrelin.

Methods

Six female patients were seen after a 12-hour fast pre-operatively and at one, three and six months post-operatively. Blood was collected before and at regular intervals after a mixed 420 kcal meal. Visual analogues scores (VAS) were used to assess satiety and nausea.

Results

The mean BMI of the patients decreased from 48.3 3 +/- 1.44 kilograms per metre squared to 36.35 +/- 1.48 kilograms per metre squared at 6 months post-op. This was accompanied by a decrease in fasting leptin from 44.7 +/- 8.1 to 13.9 +/- 2.87 nanograms per millilitre (P < 0.05). Following surgery, 15 minute postprandial GLP-1 increased from 36.6 +/- 7.2 to 151 +/-23 picomoles per litre (P < 0.05). Ninety minute plasma PYY concentrations also increased from 23.3 +/- 2.9 to 41.2 +/- 7.5 picomoles per litre (P < 0.001) and the area under the curve progressively increased at 1, 3 and 6 months (P < 0.05). There was no statistical difference in the levels of fasting ghrelin observed preoperatively or at 1, 3 and 6 months postoperatively. VAS showed a significant increase in postprandial satiety at one month postoperatively (P < 0.05), this was maintained until the end of this present study.

Conclusions

This study shows that weight loss after RYGB is accompanied by increased postprandial PYY and GLP-1. We propose that altered intestinal anatomy causes these exaggerated responses, contributing to the patients' increased satiety and weight loss. Replicating the endocrine milieu that arises as a consequence of RYGB through pharmacological may hold promise for future, effective, medical intervention in morbid obesity.