Objective: 

Intragastric devices and jejunoileal bypass are applied in obese subjects to promote weight loss. Although the mechanisms are not well-known, they simply act by reducing the amount of food needed to induce satiety. The aim was to investigate the effect of surgical procedures on plasma levels of satiety-related hormones following a liquid or a solid meal.

Methods: 

Male Sprague Dawley rats had a Roux-en-Y gastric bypass or a gastric prosthesis was sutured into fundus, while control rats had sham-surgery. In other rats, following gastric surgery, capsaicin was applied perineurally on the vagus. Three to four weeks after the surgery, either pre-weighed chow or a 3-ml non-nutrient meal was given. Thirty min after the liquid test meal and 8-h after the solid meal, rats were decapitated and trunk blood was collected for the measurement of plasma ghrelin, leptin and obestatin levels by ELISA. Values were compared by ANOVA

Results: 

In the rats with prosthesis, postprandial plasma ghrelin and obestatin levels following liquid meal were significantly lower (p<0.05) than those of the control rats, while in the bypass group ghrelin and obestatin levels were elevated with a concomitant reduction in leptin (p<0.01). Following solid meal, lower obestatin and ghrelin levels and higher leptin levels were observed in rats with prosthesis as compared to control rats (p<0.05), but in the capsaicin-treated group plasma hormone levels were not significantly different from the control values.

Conclusions: 

The present results suggest that weight-reducing effects of gastric prosthesis and bypass include the control of postprandial secretion of ghrelin, obestatin and leptin.