Duodenal nutrient infusion: effects on feeding in intact and vagotomized rabbits

A comparative study on the satiating effect of duodenal infusions of glycerol, casein and glucose was performed in intact and vagotomized rabbits during both diuranal and nocturnal periods. All duodenally infused substances had satiating effects. Glycerol infusions produced the largest reduction of food intake during the day while casein hydrolysate infusion was most effective in this respect during the night. The most apparent and consistent effect of vagotomy was the elimination of hypophagic effect of diurnal and nocturnal infusions of glucose. Pretreatment with atropine methyl nitrate, which prevented the evoked gastric contractions in response to electrical stimulation of the efferent cervical vagus nerve in acute preparations but did not influence spontaneous intake in free-feeding animals, had no effect on duodenal glucose induced satiety. This result indicates that afferent vagal mediation of information from peripheral metabolic organs is vital to the short-term glucostatic regulation of food intake.