title: L-lysine dose dependently delays gastric emptying and increases intestinal fluid volume in humans and rats.
abstract: BACKGROUND
  Novel sensory inputs for the control of food intake and gastrointestinal (GI) function are of increasing interest due to the rapid increase in nutrition-related diseases. The essential amino acid L-lysine was demonstrated to have a selective impact on food intake, gastric emptying, and intestinal transit in rats, thus indicating a potential novel direct sensory input to assess dietary protein content and quality. The aim of this study was to assess translational aspects of this finding and to investigate the dose-dependent effect of L-lysine on human and rat GI function.
  
  
  METHODS
  L-lysine doses from 0-800 mg in rats and 0.5-7.5 g in humans were analyzed for their effect on gastric emptying and GI secretion. Human GI function was assessed non-invasively using magnetic resonance imaging (MRI), rat data were acquired using standard lethal measurement methods. L-lysine dose dependently delayed gastric emptying and stimulated GI secretion in rats as reflected by residual phenol red content and increased gastric wet weight.
  
  
  RESULTS
  The dose-dependent delay in gastric emptying observed in rats was confirmed in humans with an increase in halftime of gastric emptying of 4 min/g L-lysine, p < 0.01. Moreover, a dose-dependent increase in intestinal fluid accumulation was observed (0.4 mL/min/g L-lysine, p < 0.0001). No effect on alkaline tide, glucose concentration, hematocrit, or visceral sensations was detected.
  
  
  CONCLUSIONS
  This translational study demonstrates comparable dose-dependent effects of intragastric L-lysine on GI function in humans and rats and suggests a broader role for individual amino acids in the control of GI motility and secretion in vivo.
authors.affiliation: Division of Gastroenterology and Hepatology, University of Zurich, Zurich, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Baruffol
authors.forename: J
authors.initials: J
authors.lastname: Jordi
authors.forename: S
authors.initials: S
authors.lastname: Camargo
authors.forename: T
authors.initials: T
authors.lastname: Radovic
authors.forename: B
authors.initials: B
authors.lastname: Herzog
authors.forename: M
authors.initials: M
authors.lastname: Fried
authors.forename: W
authors.initials: W
authors.lastname: Schwizer
authors.forename: F
authors.initials: F
authors.lastname: Verrey
authors.forename: T A
authors.initials: TA
authors.lastname: Lutz
authors.forename: A
authors.initials: A
authors.lastname: Steingoetter
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D001826:Body Fluids / Q000187:drug effects*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D005746:Gastric Emptying / Q000187:drug effects*; D005772:Gastrointestinal Transit / Q000187:drug effects*; D006801:Humans; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000378:metabolism; D008239:Lysine / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D051381:Rats; D017208:Rats, Wistar; D055815:Young Adult
chemical_list: D008239:Lysine
keywords: L-lysine; MRI; gastric emptying; gastrointestinal function