GLUT-5 expression in neonatal rats: crypt-villus location and age-dependent regulation.
The rat fructose transporter normally appears after completion of weaning but can be precociously induced by early feeding of a high-fructose diet. In this study, the crypt-villus site, the metabolic nature of the signal, and the age dependence of induction were determined. In weaning rats fed high-glucose pellets, GLUT-5 mRNA expression was modest, localized mainly in the upper three-fourths of the villus, and there was little expression in the villus base. When fed high-fructose pellets, GLUT-5 mRNA expression was two to three times greater in all regions except the villus base. Intestinal perfusion in vivo of a nonmetabolizable fructose analog, 3-O-methylfructose, tended to increase fructose uptake rate and moderately increased GLUT-5 mRNA abundance but had no effect on glucose uptake rates and SGLT1 mRNA abundance. Gavage feeding of high-fructose, but not high-glucose, solutions enhanced fructose uptake only in pups > or =14 days, suggesting that GLUT-5 regulation is markedly age dependent. Fructose or its metabolites upregulate GLUT-5 expression in all enterocytes, except those in the crypt and villus base and in pups <14 days old.
Jiang
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Graduate School of the Biomedical Sciences, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, New Jersey 07103-2714, USA.
David
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ES
Espina
N
N
Ferraris
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RP
D000375:Aging / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D004040:Dietary Carbohydrates / Q000494:pharmacology; D005632:Fructose / Q000031:analogs & derivatives / Q000378:metabolism / Q000493:pharmacokinetics; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000502:physiology; D005947:Glucose / Q000378:metabolism; D051296:Glucose Transporter Type 5; D066298:In Vitro Techniques; D007421:Intestine, Small / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007441:Intubation, Gastrointestinal; D009004:Monosaccharide Transport Proteins / Q000096:biosynthesis* / Q000235:genetics; D010477:Perfusion; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley
D004040:Dietary Carbohydrates; D051296:Glucose Transporter Type 5; D009004:Monosaccharide Transport Proteins; D012333:RNA, Messenger; D005632:Fructose; D005947:Glucose