c-peptide and Dumping-Syndrome

The plasma concentrations of the insulinotropic incretin hormone, glucagon-like peptide-1 (GLP-1) are abnormally high after oral glucose in partially gastrectomised subjects with reactive hypoglycaemia, suggesting a causal relationship. Because of the glucose-dependency of its effects, it is impossible to induce hypoglycaemia in normal subjects in the basal state by exogenous GLP-1, regardless of dose. To further assess the role of the incretin hormones in reactive hypoglycaemia, we reproduced the glucose and hormone profiles of the patients with reactive hypoglycaemia in 8 healthy volunteers in 4 separate protocols: 1) i.v. infusion of glucose (25 g) alone, 2) glucose together with i.v. GLP-1 infusion, and 3) and 4) glucose together with i.v. infusion of the other incretin hormone, glucose-dependent insulinotropic polypeptide (GIP), at two different infusion rates. The plasma glucose, GLP-1 and GIP concentrations (low dose) obtained were comparable with those of the patients. With GLP-1, infusion of a total of 33.4 +/- 1.3 g glucose was required to obtain plasma glucose concentrations similar to those obtained by glucose infusion alone; with low GIP, 28.0 +/- 1.2 g and with high GIP 38.4 +/- 3.5 g. Insulin concentrations increased 10-fold with GLP-1 compared with i.v. glucose alone, but less with high and low GIP. In contrast, C-peptide concentrations were similar after GLP-1 and high GIP. After termination of i.v. glucose the lowest glucose concentrations were 4.5 (3.7-4.9) (median, range) for glucose alone; 2.4 (1.9-2.8) mmol/l with GLP-1; 3.7 (2.6-4.0) with low GIP and 3.3 (2.1-4.2) with high GIP. Thus, the exaggerated GLP-1 response to nutrients in patients with accelerated gastric emptying could be responsible for their high incidence of postprandial reactive hypoglycaemia.

Topics: Adult; Blood Glucose; C-Peptide; Dumping Syndrome; Female; Gastrectomy; Gastric Emptying; Gastric Inhibitory Polypeptide; Glucagon; Glucagon-Like Peptide 1; Glucose; Humans; Hypoglycemia; Kinetics; Male; Peptide Fragments; Protein Precursors

The secretion of hormones stimulating and inhibiting gastric secretory activity was studied in 85 patients with postvagotomy syndromes. The somatropin level was found to increase significantly in gastrostasis. The lower values of the blood insulin and C-peptide content in patients with recurrent ulcers was evidently associated either with insufficiency of the pancreatic insular apparatus or with partial vagal denervation, increased STH level, and plausible inhibiting effect of glucagon. Increased somatostatin secretion in the dumping syndrome, gastrostasis, and peptic ulcers may be due to the encountered hypergastrinemia.

Topics: C-Peptide; Constriction, Pathologic; Diarrhea; Dumping Syndrome; Gastric Acid; Gastrins; Glucagon; Growth Hormone; Humans; Insulin; Insulin Secretion; Neurotransmitter Agents; Peptic Ulcer; Postoperative Complications; Recurrence; Somatostatin; Stomach Diseases; Syndrome; Vagotomy, Proximal Gastric