Hexose translocation across the blood-brain interface: configurational aspects.
The translocation of intravenously administered tritiated 3-O-methyl-D-glucopyranose (3-OMG) into brain has been studied in an intact nephrectomized rat preparation by infusing a series of hexoses into one internal carotid artery. 3-OMG rapidly penetrated into brain with peak concentrations, attained 5-8 min after injection, declining to relatively constant values thereafter. 3-OMG penetration exhibited saturation characteristics as shown by a levelling-off in the rate of translocation as its calculated blood concentration was elevated above 50 m-moles per 1000 ml. Infusion of D-galactose, D-glucose, 2-deoxyglucose, D-xylose and D-mannose significantly reduced the translocation of 3-OMG into brain on the side on which each was infused. D-glucosamine, D-mannitol and D-arabinose were without effect. The phenomenon of countertransport was demonstrated in the nephrectomized rat given tritiated 3-OMG 20 hr prior to infusion of D-glucose or D-mannose into one carotid artery. Each of these hexoses reduced brain 3-OMG concentration on the side on which it was infused. These results support the hypothesis that the translocation of certain hexoses across the blood-brain interface is a carrier-mediated process.
Bidder
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Department of Psychiatry, Case Western Reserve University, School of Medicine, University Circle, Cleveland, Ohio 44106, USA.
D019325:3-O-Methylglucose / Q000493:pharmacokinetics; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006601:Hexoses / Q000378:metabolism* / Q000494:pharmacology; D009392:Nephrectomy / Q000379:methods; D051381:Rats; D013997:Time Factors
D006601:Hexoses; D019325:3-O-Methylglucose