Abstract
By immunocytochemistry we have studied the effect of recombinant human insulin-like growth factor I (rhIGF-I) on expression of renal GLUT-1, -2, and -5 in rats with streptozotocin (STZ)-induced diabetes. In the renal tubules of these rats, expression of GLUT-1 was reduced and that of GLUT-2 was increased. GLUT-1 expression was restored, and GLUT-2 expression was normalized by 2-wk administration of rhIGF-I. We have shown that GLUT-5 was expressed at the brush-border membrane of the proximal convoluted tubules (PCT) of the cortex and at the glomerular mesangial cells (GMC) in normal rat kidney. In the diabetic rats, GLUT-5 expression was increased at both sites, along with an increase of GLUT-2 expression at the basolateral membrane of PCT, and was decreased to normal level at both sites by treatment with rhIGF-I. Thus, like GLUT-2, GLUT-5 is suggested to regulate glucose reabsorption in PCT. The relationship between overexpression of GLUT-5 in GMC and accumulation of sorbitol and advanced glycosylation end products are discussed. Regulation of GLUT expression may play an important role on renal glucose homeostasis.
MeSH terms
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Analysis of Variance
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Animals
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Body Weight / drug effects
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Cell Membrane / metabolism
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Diabetes Mellitus, Experimental / metabolism*
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Diabetes Mellitus, Experimental / physiopathology
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Diabetic Nephropathies / physiopathology
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Gene Expression / drug effects
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Glomerular Mesangium / metabolism
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Glucose Transporter Type 1
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Glucose Transporter Type 2
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Glucose Transporter Type 4
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Glycogen / metabolism
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Humans
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Immunohistochemistry
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Insulin / pharmacology
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Insulin-Like Growth Factor I / pharmacology*
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Kidney / drug effects
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Kidney / metabolism*
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Kidney / physiopathology
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Kidney Cortex / metabolism
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Kidney Tubules, Proximal / metabolism
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Male
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Microvilli / metabolism
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Models, Biological
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Monosaccharide Transport Proteins / biosynthesis*
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Muscle Proteins*
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Organ Size / drug effects
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Rats
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Rats, Sprague-Dawley
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Recombinant Proteins / pharmacology
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Reference Values
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Weight Gain / drug effects
Substances
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Glucose Transporter Type 1
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Glucose Transporter Type 2
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Glucose Transporter Type 4
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Insulin
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Monosaccharide Transport Proteins
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Muscle Proteins
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Recombinant Proteins
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SLC2A1 protein, human
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SLC2A4 protein, human
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Slc2a1 protein, rat
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Slc2a4 protein, rat
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Insulin-Like Growth Factor I
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Glycogen