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Glucose transport is reduced in the blood-brain barrier of aged rats
Ist Teil von
Brain research, 1991-06, Vol.551 (1), p.145-149
Ort / Verlag
London: Elsevier B.V
Erscheinungsjahr
1991
Link zum Volltext
Quelle
Elsevier ScienceDirect Journals
Beschreibungen/Notizen
To determine the biochemical basis of decreased brain uptake of glucose with age, the brain influx of 3-
O-methylglucose (3-O-MG) was measured in male Fischer 344 rats at various ages using the arterial injection-tissue sampling technique of Oldendorf. The
V
max of 3-O-MG transport in the 24-month-old rats (0.22 ± 0.14 μmol/min/g) was significantly lower than than in 3-month-old rats (0.88 ± 0.18 μmol/min/g)(
P < 0.050). The
K
m of transport in aged rats (10.1 ± 4.8mM) was not different from that in young rats (8.1 ± 2.5mM). The cytochalasin B binding sites in cerebral microvessels isolated from aged rats (13.9 ± 0.9pmol/mg) compared to the binding sites in cerebral microvessels of young rats (21.9 ± 1.4pmol/mg) were significantly reduced (
P < 0.001). However, the immunoreactive mass of glucose transporter of cerebral microvessels was not altered with age. The enrichment of capillary preparations with gamma-glutamyl transpeptidase activity, a marker of endothelial cells, was not altered in aged rats, suggesting that the reduced blood-brain barrier transport of glucose is due to specific reduction in glucose binding sites of the transporter rather than secondary to a non-specific age-related effect of endothelial cell drop-out.