Disease relevance of GLUT-3

• GLUT-3 concentrations declined at 17-20 days of chronic hyperglycemia (P < 0.05), associated with increased uterine and uteroplacental net glucose uptake rate, but a normal fetal glucose uptake rate was observed [1].
• Chronic hypoglycemia did not change GLUT-3 concentrations, although uterine, uteroplacental, and fetal net glucose uptake rates were decreased [1].
• The acute effect of selective hyperglycemia or hyperinsulinemia on late gestation fetal ovine glucose transporter protein (GLUT-1, GLUT-3, and GLUT-4) concentrations was examined in insulin-insensitive (brain and liver) and insulin-sensitive (myocardium and fat) tissues at 1, 2.5, and 24 h [2].

High impact information on GLUT-3

• Cortisol treatment had no apparent effect on placental mRNA expression for the glucose transporters, GLUT-1 and GLUT-3 [3].
• The transplacental glucose gradient was increased twofold in the H+GH group but placental GLUT- 1 and GLUT-3 expression was unaffected [4].
• Betamethasone did not alter GLUT1 and GLUT3 immunoreactivity in any of the brain regions investigated, independently of the dose and route of administration [5].
• Glucose uptake into cerebral neurons is selectively facilitated by glucose transporter protein GLUT1 in the blood brain barrier and GLUT3 in neuronal membranes [5].
• GLUT1 and GLUT3 immunoreactivity was examined in fetal sheep brain sections of the frontal neocortex, caudate putamen and hippocampus at 0.73 gestation after fetal exposure to betamethasone by direct fetal intravenous infusion or maternal intramuscular injections at the clinically relevant dosage [5].

Biological context of GLUT-3

• The ovine GLUT-3 cDNA is 3854 base pairs and the coding nucleotides show 82% and 79% homology with the human and mouse GLUT-3 sequences respectively [6].
• This report describes the isolation and sequencing of the full length ovine GLUT-3 cDNA and the tissue distribution of ovine GLUT-1 and GLUT-3 mRNA [6].
• These cellular adaptations in GLUT-1 (and GLUT-3) are geared toward protecting the conceptus from perturbations in substrate availability, and the adaptations in GLUT-4 are geared toward development of fetal insulin resistance [7].
• Glucose transporters include the GLUT1 and GLUT3 isoforms previously identified in brain and other tissues; systems for active transport of amino acids have been inferred but not characterized [8].

Anatomical context of GLUT-3

• GLUT-3 was limited to the apical surface of the trophoectoderm, whereas GLUT-1 was on the basolateral and apical surfaces of this cell layer and in the epithelial cells lining the placental uterine glands [1].

References