Role of the Vagus Nerve in Mediating Proximal Nutrient-Induced Glucagon-Like Peptide-1 Secretion*

• DOI: 10.1210/endo.140.4.6643
• Publication Date: 2014-01-08T16:10:00Z
• Authors: A. S. Rocca; P. L. Brubaker
• Keywords: Blood Glucose; Male; Duodenum; Vagus Nerve; Gastric Inhibitory Polypeptide; Vagotomy; Glucagon; Electric Stimulation; Peptide Fragments; Rats; 3. Good health; Kinetics; 03 medical and health sciences; 0302 clinical medicine; Glucagon-Like Peptide 1; Animals; Humans; Corn Oil; Protein Precursors; Rats, Wistar; Peptides

Plasma levels of glucagon-like peptide-1 (GLP-1) rise rapidly after nutrient ingestion, suggesting the existence a proximal gut signal regulating GLP-1 release from L cells distal small intestine. Glucose-dependent insulinotropic peptide (GIP) has been shown to be one such signal; however, dependence GIP on gastrin-releasing peptide, neuromodulator, suggested role for nervous system in this proximal-distal loop. Investigations into nature were therefore conducted an situ model rat gastrointestinal system. Infusions corn oil 10-cm segment duodenum that was isolated by loose ligation (to ensure luminal contents did not progress ileal cell) increased secretion parallel with immunoreactivity (gGLI; r = 0.85; P < 0.05). Infusion fat transected also significantly raised gGLI compared saline infusion, reaching peak value 132 +/- 37 pg/ml above basal (P However, delayed when alone (19 4 vs. 6 1 min, respectively; Furthermore, bilateral subdiaphragmatic vagotomy conjunction transection completely abolished fat-induced 0.001). Consistent vagus regulation cell, stimulation end celiac branch nerve stimulated level 71 14 As found previously, supraphysiological infusion control animals 123 32 0.05); prevented hepatic (96 25 pg/ml; In contrast, although at physiological sham-vagotomized secretion, 40 0.05), selective GIP-induced The results these experiments demonstrate and cell response is regulated complex neuroendocrine loop, involving enteric system, afferent efferent nerves, as well duodenal hormone GIP.