The Ontogeny of the Rabbit Brain Glucose Transporter*

Sadiq, F; Holtzclaw, Lynne A.; Chundu, Koteswara R.; Muzzafar, A.; Devaskar, Sherin U.

doi:10.1210/endo-126-5-2417

Cited by 72 publications

(24 citation statements)

References 29 publications

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“…As expected, the insulin-sensitive transporter, GLUT4, was not detected in homogenates of whole brain (Sadiq et al 1990). GLUT2, the low-affinity transporter of the liver and pancreas, also has not been found in whole brain (Thorens et al 1988).…”

Section: I S T R I B U T I O N Of G L U C O S E T R a N S P O R T Esupporting

confidence: 75%

Glucose transporters in the brain

Rayner¹

1996

Proc. Nutr. Soc.

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Les transporteurs du glucose dans le cerveau R E S U M ETous les tissus possedent une ou plusieurs familles de transporteurs facilitants du glucose (GLUT). Les transporteurs du glucose sont particulikrement importants dans le cerveau car la barrikre entre le sang et le cerveau est impermkable 21 des molCcules polaires telles que les glucose, et pourtant cet organe requiert des quantitCs importantes de glucose qui est sa principale source d'Cnergie. Le transport facilitC du glucose dans le cerveau n'est pas dCpendant de l'insuline et implique principalement deux isoformes de transporteurs GLUTl et GLUT3. GLUTl se trouve dans les membranes luminale et abluminale de I'endothClium capillaire (c'est-a-dire la barrikre entre le sang et le cerveau). I1 se trouve Cgalement a un moindre niveau de glycosylation dans le parenchyme du cerveau, oh il est le transporteur du glucose des cellules gliales. GLUT3 se trouve essentiellement dans les neurones. Les hautes affinites pour le glucose de GLUTl et GLUT3 assurent un apport adCquat de glucose aux neurones et minimisent les effets des modifications de la concentration du glucose. La rCpartition des transporteurs du glucose est modifiCe dans le cerveau en dkveloppement. Au dCbut de la gestation, avant la fermeture de la barrikre entre le sang et le cerveau, GLUTl est prCsent dans tout le neuropil; plus tard dans la gestation on trouve GLUTl en majeure partie dans les vaisseaux sanguins. Apres la naissance, GLUTl est rCgulC a la baisse avant le sevrage, oh le cerveau dCpend moins du glucose comme source d'Cnergie. GLUT3 augmente progressivement apres la naissance tandis que s'effectue la maturation des neurones. Les transporteurs du glucose rCpondent aux demandes nutritionnelles et mktaboliques telle que le froid ou le j e h e pour maintenir l'apport de glucose. On ne sait pas bien comment GLUTl est rCgulC, mais il semble probable que le degrC de glycosylation et le nombre de molCcules de transport du glucose sur la membrane des cellules jouent un r81e dans cette rkgulation. Les niveaux des transporteurs du glucose dans le cerveau sont modifiCs dans la maladie. Dans la maladie d'Alzheimer, qui implique la destruction dCgCnCrative des cellules du cerveau et une diminution du mCtabolisme du glucose, les transporteurs du glucose diminuent en gCn6ral. Dans les tumeurs du cerveau on voit l'augmentation du m6tabolisme du glucose, mais aussi une plus grande permCabilit6 de la barriere entre le sang et le cerveau; GLUTl est parfois, mais pas toujours, absent, et peut Ctre un marqueur de dCveloppement d'une tumeur. Enfin, on a avancC que les transporteurs du glucose feraient partie des mdcanismes de sensibilite au glucose dans le cerveau. I1 se peut qu'une rdpartition discrete dan les regions du cerveau connues pour &re sensibles au glucose marquent leur implication et expliquent le r8le du cerveau dans la rigulation du mCtabolisme. Le transporteur sensible l'insuline, GLUT4 a CtC retrouvC dans l'hypothalamus et le cervelet, tandis que GLUT2 (transporteur faible affinitk du foie et du ...

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Section: I S T R I B U T I O N Of G L U C O S E T R a N S P O R T Esupporting

confidence: 75%

Glucose transporters in the brain

Rayner¹

1996

Proc. Nutr. Soc.

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“…As in cattle (present study), GLUT1 expression has also been shown to be maximal in early foetal life and to decrease steadily throughout gestation in the heart and skeletal muscle of the chicken [33]. Some species-specific regulation has, however, been demonstrated: GLUT1 expression at both the protein and mRNA levels is indeed shown to decrease after birth in the rat heart [11] and in the brain, lung, liver and kidney of rodents [34][35][36], whereas the GLUT1 level does not change in the skeletal muscle and adipose tissue of Holstein male calves from birth to 12 months of age [37]. Our study confirmed that birth is not associated with major and statistically significant changes in GLUT1 expression in either heart or adipose tissue of cattle.…”

Section: Ontogenesis Of Glucose Transporterssupporting

confidence: 67%

Prenatal developmental changes in glucose transporters, intermediary metabolism and hormonal receptors related to the IGF/insulin-glucose axis in the heart and adipose tissue of bovines

et al. 2006

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-Glucose transporter ontogenesis is likely to play a key role in glucose uptake by foetal tissues in order to satisfy their energy requirements. We thus investigated developmental changes in the bovine heart and perirenal adipose tissue in two glucose transporter isoforms, namely GLUT1 and GLUT4, the latter being responsible for the regulation of glucose uptake by insulin. Other key players of the glucose/insulin axis were also assessed. Plasma glucose concentration in the foetus was lower at 8 and 8.5 months of age than previously. In the heart, GLUT1 protein level markedly decreased between 3 and 4 months of age, whereas the number of insulin and IGF-I binding sites continually decreased, especially between 7 and 8 or 8.5 months of age. On the contrary, the GLUT4 level increased until 8 months of age and remained high until 2 weeks after birth. The activities of enzymes of glucose metabolism (namely phosphofructokinase [PFK] and lactate dehydrogenase [LDH]) increased throughout gestation and reached a plateau at 6 and 8.5 months of age for PFK and LDH, respectively. The activities of enzymes involved in fatty acid metabolism increased especially at birth. In perirenal adipose tissue, high mitochondrial activity was detected before birth which is a characteristic of brown adipose tissue. Furthermore, lipoprotein lipase activity and GLUT4 protein level markedly increased to reach a maximum at 6-7 and 8 months of age, and sharply decreased thereafter, whereas GLUT1 protein level increased between 6 and 7 months of age. In conclusion, considerable changes in the regulation of the insulin/glucose axis were observed from 6 months onwards of foetal development in both the heart and adipose tissue of cattle, which probably alters the potential of these tissues to use glucose or fat as energy sources.

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“…Glut 3 has been found in small amounts in fetal and newborn rabbit brain (8). Our data suggest that little Glut 3 (as measured by the mouse cDNA probe) is expressed in the fetal rat brain and even less is expressed in lung.…”

Section: Brain Lungmentioning

confidence: 57%

“…cDNA encoding a glucose transporter have been cloned from both rat brain and human hepatoma (Hep G2) cell libraries (6,7). This glucose transporter has been termed Glut 1 and is present in most fetal tissues including brain (8,9). Glut 3, originally cloned from human fetal skeletal muscle, has been found in small quantities in fetal rabbit brain (9).…”

mentioning

confidence: 99%