title: Prolonged effects of modified sham feeding on energy substrate mobilization.
abstract: BACKGROUND
  Vagal stimulation in response to nutrients is reported to elicit an array of digestive and endocrine responses, including an alteration in postprandial lipid metabolism.
  
  
  OBJECTIVE
  The objective of this study was to assess whether neural stimulation could alter hormone and substrate metabolism during the late postprandial phase, with implications for body fat mobilization.
  
  
  METHODS
  Vagal stimulation was achieved by using the modified sham feeding (MSF) technique, in which nutrients are chewed and tasted but not swallowed. Ten healthy subjects were studied on 3 separate occasions, 4 wk apart. Five hours after a high-fat breakfast (56 g fat), the subjects were given 1 of 3 test meals allocated in random order: water, a lunch containing a modest amount of fat (38 g), or MSF (38 g fat). Blood was collected for 3 h poststimulus for hormone and metabolite analyses.
  
  
  RESULTS
  Plasma insulin and pancreatic polypeptide concentrations peaked at 250% and 209% of baseline concentrations within 15 min of MSF. The plasma glucose concentration increased significantly (P = 0.038) in parallel with the changes observed in the plasma insulin concentration. The nonesterified fatty acid concentration was significantly suppressed (P: = 0.006); maximum suppression occurred at a mean time of 114 min after MSF. This fall in nonesterified fatty acid was accompanied by a fall in the plasma glucagon concentration from 122 to 85 pmol/L (P = 0.018) at a mean time of 113 min after MSF.
  
  
  CONCLUSIONS
  Effects on substrate metabolism after MSF in the postprandial state differ from those usually reported in the postabsorptive state. The effects of MSF were prolonged beyond the period of the cephalic response and these may be relevant for longer-term metabolic regulation.
authors: Oxford Lipid Metabolism Group, the Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom. denise.robertson@oxlip.ox.ac.uk
authors: M D
authors: MD
authors: Robertson
authors: K G
authors: KG
authors: Jackson
authors: C M
authors: CM
authors: Williams
authors: B A
authors: BA
authors: Fielding
authors: K N
authors: KN
authors: Frayn
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002766:Cholecystokinin / Q000097:blood; D004041:Dietary Fats / Q000008:administration & dosage*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005755:Gastrins / Q000097:blood; D005934:Glucagon / Q000097:blood; D006728:Hormones / Q000097:blood*; D006801:Humans; D007328:Insulin / Q000097:blood; D050356:Lipid Metabolism; D008297:Male; D008875:Middle Aged; D010191:Pancreatic Polypeptide / Q000097:blood; D019518:Postprandial Period / Q000502:physiology*; D013997:Time Factors; D014280:Triglycerides / Q000097:blood; D014630:Vagus Nerve / Q000502:physiology*
chemical_list: D001786:Blood Glucose; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D005755:Gastrins; D006728:Hormones; D007328:Insulin; D014280:Triglycerides; D010191:Pancreatic Polypeptide; D005934:Glucagon; D002766:Cholecystokinin