HEPATIC BRANCH VAGOTOMY ENHANCES GLUCOPRIVIC FEEDING IN FOOD-DEPRIVEDOLD RATS

Glucoprivic feeding induced by intraperitoneal (IP) injection of 2-deo xy-D-glucose (2-DG, 250 mg/kg body weight) in the middle of the light phase was investigated in old (age: 15-16 months) and young (age: 2.5- 3.5 months) hepatic branch-vagotomized (HBV) and sham-vagotomized (SV) rats. Rats were fed either a carbohydrate-rich diet or a fat-enriched diet with a moderate carbohydrate content. The glucoprivic feeding re sponse was greater in 13-h food-deprived old HBV rats than in 13-h foo d-deprived old SV rats on both diets. 2-Deoxy-D-glucose produced a gre ater feeding response when rats were fed the fat-enriched diet. Indepe ndent of the diet, the transient hyperphagia induced by 2-DG was follo wed by a long-term hypophagia in old SV rats, but not in old HBV rats. In 13-h food-deprived young rats, hepatic branch vagotomy did not aff ect the changes in food intake induced by 2-DG. In undeprived old and young rats, the feeding response to 2-DG, exceeding that of deprived r ats, was also not affected by HBV. It is concluded that under certain conditions hepatic branch vagotomy eliminates a 2-DG-induced signal in hibiting food intake and thus enhances glucoprivic feeding. The feedin g response to 2-DG therefore seems to depend on stimuli affecting food intake in an antagonistic manner.