Effect of total colectomy and PYY infusion on food intake and body weight in rats.

PYY (3-36) is postulated to act as a satiety factor in the gut-hypothalamic pathway to inhibit food intake and body weight gain in humans and rodent models. We determined the effect of 14-day continuous intravenous infusion of PYY (3-36) (175 microg/kg/day) on food intake and body weight gain in colectomized male Wistar rats. Colectomy caused an increase in plasma PYY levels at 7 days which was reduced at 14 days but still significantly elevated compared to basal preoperative values. Animals treated with continuous PYY (3-36) infusion had significantly elevated PYY levels compared to the control group throughout the whole experiment, but showed a similar pattern of food intake and body weight gain. In conclusion, although continuous intravenous infusion is the most physiologically relevant method to mimic high postprandial PYY levels, we did not observe any significant effect on food intake and body weight gain in non-food deprived colectomized animals. This suggests that PYY has, if at all, only a minor role in food intake in rats.