Fructose transport by rat intestinal brush border membrane vesicles. Effect of high fructose diet followed by return to standard diet.
1. D-Fructose uptake in isolated rat intestinal brush border membrane comprised a simple diffusional component and a saturable, carrier-mediated, component. The latter did not follow typical Michaelis-Menten kinetics and appeared as a low affinity, high capacity process (Kt = 110 mM, Jmax = 160.5 nmol/min.mg protein). 2. Carrier-mediated D-fructose uptake was highly specific, Na independent and unaffected by phloridzin and metabolic inhibitors. 3. Fructose feeding for 3 days resulted in an activation of D-fructose uptake after a latent period superior to 3 days. The increase was of relatively short duration since it was not further observed 6 days after the return to the standard diet. 4. The activation in D-fructose uptake was due to a slight decrease in Kt and a marked increase in Jmax (from 160.5 to 306 nmol/min.mg protein), suggesting a rise in the number of transporters.
Laboratoire de Physiologie Générale et Comparée, Université Claude Bernard, Lyon, France.
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Crouzoulon
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Korieh
D000818:Animals; D001692:Biological Transport; D004032:Diet; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D005632:Fructose / Q000008:administration & dosage / Q000378:metabolism*; D006601:Hexoses / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000187:drug effects; D008297:Male; D008871:Microvilli / Q000187:drug effects / Q000378:metabolism*; D010695:Phlorhizin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013379:Substrate Specificity
D004040:Dietary Carbohydrates; D006601:Hexoses; D005632:Fructose; D010695:Phlorhizin