Altered endocrine pancreatic function following vagotomy: possible behavioral and metabolic bases for assessing completeness of vagotomy.

Total vagotomy induces multiple alterations in the function of the endocrine pancreas. The temporal evolution of selected behavioral and pancreatic alterations following subdiaphragmatic vagotomy was investigated. Sustained modifications were observed in the circadian rhythm of plasma insulin, beta-cell responses to glucose and acetylcholine, whole system response to oral, but not intravenous, glucose and meal frequency. Transient alterations occurred in plasma insulin concentrations, peak glucose response to oral glucose, body weight, food intake, dark-phase meal size and light/dark food intake ratio. Since a major methodological problem in studies of the effects of vagotomy remains the assessment of the completeness of nerve section, the efficiency of several validation tests based on pancreatic alterations were investigated. Of these possible tests, the marked changes in the time-course of blood glucose following oral glucose administration and the in vivo assessment of acetylcholine sensitivity appear to be the most promising. Among other tests investigated, the water intake/100 g body weight and the stomach weight/body weight ratio had high efficiencies. It is recommended that a combination of objective tests, appropriate to the specific study, with varying degrees of invasiveness be used to assess the completeness of vagotomy.