title: Enteral glutamine supplementation impairs intestinal blood flow in rats.
abstract: BACKGROUND
  Clinical studies have shown that enteral immune-enhancing diets (IEDs) containing l-glutamine decrease septic complications and length of stay in some patient populations. Animal studies suggest IED benefits might include augmented gut blood flow. We hypothesized that enteral glutamine supplementation modulates gastrointestinal blood flow.
  
  
  METHODS
  Blood flow was measured in male Sprague-Dawley rats via the colorimetric microsphere technique at baseline, 60, and 120 minutes. Four groups were studied: (1) control diet (CD) + enteral glutamine; (2) CD + enteral glycine; (3) CD + enteral saline; and (4) CD + intravenous glutamine.
  
  
  RESULTS
  There were no differences in blood pressure or heart rate in any group. Group 1 blood flow was decreased at 120 minutes compared with controls (groups 2 and 3) in small intestine, colon, spleen, and pancreas, whereas the intravenous glutamine group (group 4) had no effect on blood flow.
  
  
  CONCLUSIONS
  Enteral glutamine supplementation (as in IEDs) appears to impair gastrointestinal blood flow. Because glutamine provides energy directly to active enterocytes, enteral glutamine availability might diminish metabolic stimuli of absorptive hyperemia. This finding might partially explain the benefits observed with parenteral versus enteral glutamine supplementation in clinical studies (such as bone-marrow-transplant patients).
authors.affiliation: Department of Surgery, University of Louisville, 800 Zorn Ave., Research Building 19, Louisville, KY 40206, USA. paul.matheson@louisville.edu
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Matheson
authors.forename: Brady T
authors.initials: BT
authors.lastname: Harris
authors.forename: Ryan T
authors.initials: RT
authors.lastname: Hurt
authors.forename: E Rasheid
authors.initials: ER
authors.lastname: Zakaria
authors.forename: R Neal
authors.initials: RN
authors.lastname: Garrison
mesh_terms: D000818:Animals; D003124:Colorimetry; D004750:Enteral Nutrition; D005973:Glutamine / Q000008:administration & dosage / Q000009:adverse effects*; D007422:Intestines / Q000098:blood supply*; D008297:Male; D010179:Pancreas / Q000098:blood supply; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects*; D013154:Spleen / Q000098:blood supply
chemical_list: D005973:Glutamine