Body weight and gastric acid secretion in rats with subdiaphragmatic vagotomy and lateral hypothalamic lesions

In an experiment to investigate the role of the vagus in the lateral hypothalamic (LH) syndrome of body weight loss, male albino rats were divided into four groups: (a) animals with bilateral LH lesions that were subsequently given a bilateral subdiaphragmatic vagotomy, (b) LH animals that received a control vagotomy operation, (c) nonlesion animals that were given a subdiaphragmatic vagotomy operation, (c) nonlesion animals that were given a subdiaphragmatic vagotomy, and (d) nonlesion animals that received a control vagotomy operation. Both LH lesions and vagotomy reduced body weight levels, though the effects differed in terms of the length of time required to reach initial maximal loss, the time required to reach chronic levels of maintenance, and the severity of body weight reduction. Fasting gastric acid secretion was lowered by LH lesions, and the extent of this reduction was positively correlated with the reduction in body weight. Finally, gastric contents after a 24-hr fast were greater in vagotomized rats than in nonvagotomized animals. These data are discussed in relation to the changes in gastric functioning after LH lesions and vagotomy.