title: Effect of energy substrates on protein degradation in isolated small intestinal enterocytes from rats.
abstract: BACKGROUND
  Nutrients affect small intestinal protein mass and metabolism, but studies on the effect of nutrients on small intestinal protein degradation are very limited due to a lack of a proper method. The objectives of this study were to establish a method to directly estimate protein degradation in isolated enterocytes from rats and to test the effect of energy substrates on protein degradation.
  
  
  METHODS
  Male Sprague-Dawley rats (150-200 g, n>or=8 per treatment) were used. Cell viability, tyrosine release as an indicator of protein degradation, and the effect of osmolarity, 50 mmol/L glucose, 20 mmol/L beta-hydroxybutyrate, 4.7 mmol/L butyrate, and 30 mmol/L glutamine on protein degradation were measured.
  
  
  RESULTS
  The average viability of enterocytes at time 30 minutes was 85.8% (range, 81%-94%). Tyrosine release was linear over the course of experiments, indicating constant protein degradation (R2=0.9943; p<.05). Osmolarity, glucose, and glutamine had no effect on protein degradation in isolated enterocytes. Beta-hydroxybutyrate significantly decreased it (-16%; p<.05), whereas butyrate slightly increased it (+5%; p<.05).
  
  
  CONCLUSIONS
  A high viability and constant protein degradation indicate a successful establishment of a method to estimate protein degradation in isolated small intestinal enterocytes from rats. The large effect of beta-hydroxybutyrate suggests a potential positive role for ketone bodies to limit the loss of small intestinal protein mass by decreasing protein degradation.
authors.affiliation: Food, Nutrition and Health, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Mohsen T
authors.initials: MT
authors.lastname: Saberi
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Stewart
authors.forename: Myriam
authors.initials: M
authors.lastname: Annette
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Knowles
authors.forename: Didier
authors.initials: D
authors.lastname: Attaix
authors.forename: Sue E
authors.initials: SE
authors.lastname: Samuels
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000378:metabolism / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D004734:Energy Metabolism / Q000502:physiology; D020895:Enterocytes / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D005973:Glutamine / Q000378:metabolism / Q000494:pharmacology; D007421:Intestine, Small / Q000166:cytology* / Q000378:metabolism*; D008297:Male; D009994:Osmolar Concentration; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014443:Tyrosine / Q000032:analysis / Q000378:metabolism
chemical_list: D011506:Proteins; D005973:Glutamine; D014443:Tyrosine; D005947:Glucose; D020155:3-Hydroxybutyric Acid