The effect of truncal and selective vagotomy on the release of pancreatic glucagon, insulin and enteroglucagon

Abstract

SUMMARYTo study the effect of vagotomy on the endocrine function of the pancreas, plasma pancreatic glucagon levels were studied during insulin-induced hypoglycaemia, and VAGOTOMY in one of its various forms is the most widely practised surgical treatment for chronic duodenal ulcer, but there remains controversy as to which variant is preferable. The theoretical argument in favour of selective vagotomy is that it preserves the vagal innervation of the pancreas and liver, but there is surprisingly little information about the effect of truncal and selective vagotomy on pancreatic function.On the basis of its amylase output in response to insulin-induced hypoglycaemia, McKelvey et al. (1973) have shown that the exocrine function of the pancreas is reduced by truncal vagotomy compared with selective vagotomy. There is some evidence from animal studies that vagal stimulation results in the release of glucagon (Bloom et a]., 1974) and of insulin (Daniel and Henderson, 1967), but the effect of vagotomy on pancreatic endocrine function in man has not been studied, and indeed there is no evidence that in man vagal innervation plays any part in the control of the secretion of insulin and glucagon. The present investigation was performed to see whether the endocrine function of the pancreas was differently affected by truncal and selective vagotomy, as judged by the plasma levels of pancreatic glucagon during insulin-induced hypoglycaemia and the plasma insulin levels after the ingestion of glucose.Preliminary studies have demonstratcd that the levels of plasma enteroglucagon in response to oral glucose are greater following vagotomy and a drainage procedure than in normal people (Bloom et al., 1972), but the numbers studied were too small to determine whether there was any difference between truncal and selective vagotomy. Further studies have been performed to clarify this point. On the basis of the result of the insulin test the patients who had had a complete vagotomy by the criteria of Hollander (1948) were selected for this study. There were 24 patients after truncal vagotomy and 17 patients after selective vagotomy chosen for investigation. All the patients had had a drainage procedure with the vagotomy, either a pyloroplasty or gastrojejunostomy. The groups selected were similar in all respects. Materials and methods Clinical Insulin and enteroglucagon release after oral glucose:After an overnight fast 16 patients who had undergone a truncal vagotomy and 21 patients who had undergone a selective vagotomy were challenged with oral hypertonic glucose (200 ml of a 50 per cent solution). All the patients had had a drainage procedure with the vagotomy, either a pyloroplasty or a gastrojejunostomy. The groups were similar in all respects. Blood samples were taken in the same manner as described above; two samples prior to the glucose meal, and at 10, 20, 30, 40, 60, 90 and 120 minutes after the challenge. The plasma insulin concentration, the plasma enteroglucagon concentration and the blood sugar concentration were me...

Effect of vagotomy on gastrointestinal hormones

“…Lefebvre and colleagues [69] observed no glucagon release from the stomach during electrical vagal stimulation. Russell and colleagues [61] found no difference in plasma enteroglucagon levels when comparing patients with TV and SGV plus P.…”

“…In studies using the isolated, perfused rat pancreas, acetylcholine induced a prompt release of insulin [57], and direct vagal stimulation resulted in a release of insulin [58,59]. Several studies [60][61][62][63] have demonstrated that after SPV or SGV plus P, basal serum insulin levels and the postprandial insulin output were not changed. After TV, the insulin response to an oral glucose tolerance test or a test meal was either diminished [60,62] or unchanged [61,63,64].…”

“…Several studies [60][61][62][63] have demonstrated that after SPV or SGV plus P, basal serum insulin levels and the postprandial insulin output were not changed. After TV, the insulin response to an oral glucose tolerance test or a test meal was either diminished [60,62] or unchanged [61,63,64].…”

“…Like insulin, pancreatic glucagon is released by vagal stimulation from the pancreas [58]. In studies of the pancreatic glucagon release during insulin hypoglycemia in patients with either SGV or TV, Russell and colleagues [61] found no change in basal glucagon levels, but significantly lower glucagon concentrations after insulin injection in TV patients, compared to SGV patients.…”

Hormonal responses to insulin infusion in diabetes mellitus

“…The presence of a glucagon response to arginine in the patients tested in Group B is evidence of the presence of functional A cells, despite the low glucagon response during insulin infusion. Glucagon release during minor hypoglycaemia is under vagal control from a central glucoreceptor [10,11] rather than under direct control by circulating glucose levels. Our previous hypothesis that the impaired glucagon response was due to a selective form of autonomic neuropathy [3] cannot, however, explain the impaired responses in cortisol and growth hormone.…”