Hypoxia differentially regulates nutrient transport in rat jejunum regardless of luminal nutrient present.
Aggressive enteral nutrition and poor intestinal perfusion are hypothesized to play an important pathogenic role in nonocclusive small bowel necrosis. This study tests the hypothesis that glucose and glutamine transport are differentially regulated during hypoxia regardless of the luminal nutrient present. Sprague-Dawley rats (247 +/- 3 g; n = 16) were randomized to receive 1 h of intestinal hypoxia or serve as normoxic controls. During this hour, jejunal loops were randomized to receive in situ perfusions of mannitol, glucose, or glutamine. When compared with normoxic groups, glucose but not glutamine transport was impaired (P < 0.001) during hypoxia. Messenger RNA abundance of the sodium glucose cotransporter sodium-dependent glucose cotransporter-1 (SGLT-1) and neutral basic amino acid transporter B(o) did not differ with hypoxia or nutrient perfused. Jejunal brush-border SGLT-1 abundance was decreased (P = 0.039) with hypoxia; however, total cellular SGLT-1 protein abundance did not differ among treatment groups. These data indicate that SGLT-1 activity is regulated during hypoxia at the posttranslational level. Additional information regarding the mechanisms regulating nutrient transport in the hypoperfused intestine is critical for optimizing the composition of enteral nutrient formulas.
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Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Tappenden
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D000244:Adenosine Diphosphate / Q000032:analysis; D000255:Adenosine Triphosphate / Q000032:analysis; D026962:Amino Acid Transport System ASC / Q000235:genetics; D000818:Animals; D001692:Biological Transport; D005947:Glucose / Q000008:administration & dosage / Q000378:metabolism*; D005973:Glutamine / Q000008:administration & dosage / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism*; D007408:Intestinal Absorption; D007583:Jejunum / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D008353:Mannitol / Q000008:administration & dosage / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics; D015778:Minor Histocompatibility Antigens; D009004:Monosaccharide Transport Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051269:Sodium-Glucose Transporter 1
D026962:Amino Acid Transport System ASC; D008562:Membrane Glycoproteins; D015778:Minor Histocompatibility Antigens; D009004:Monosaccharide Transport Proteins; D012333:RNA, Messenger; C498849:Slc1a5 protein, rat; C495676:Slc5a1 protein, rat; D051269:Sodium-Glucose Transporter 1; D005973:Glutamine; D008353:Mannitol; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D005947:Glucose