title: Comparison of glucose influx and blood flow in retina and brain of diabetic rats.
abstract: Diabetes is associated with extensive microvascular pathology and decreased expression of the glucose transporter (GLUT-1) in retina, but not brain. To explore the basis of these differences, the authors simultaneously measured glucose influx (micromol x g(-1) x min(-1)) and blood flow (mL x g(-1) x min(-1)) in retina and brain cortex of nondiabetic control rats (normoglycemic and acute-hyperglycemic) and in rats with streptozotocin-induced diabetes (with or without aminoguanidine (AMG) treatment) using a single-pass, dual-label indicator method. In addition, tissue glucose and adenosine triphosphate (nmol/mg dry weight) levels were measured. Glucose influx in retina exceeded that of cortex by about threefold for both the nondiabetic and diabetic groups. In contrast, blood flow in retina was significantly lower than in cortex by about threefold for each group. Retinal and cortical glucose influx in the diabetic rats was lower than in the nondiabetic acute-hyperglycemic group, but not in the normoglycemic group. Blood flow in these tissues remained relatively unchanged with glycemic conditions. The glucose levels in the diabetic retina (aminoguanidine untreated and aminoguanidine treated) were fourfold to sixfold greater than the nondiabetic retina. The cortical glucose levels remained unchanged in all groups. These data suggest that the accumulation of glucose in the diabetic retina cannot be explained by increased endothelial-glucose uptake or increased vascular membrane permeability.
authors.affiliation: Department of Anatomy, Case Western Reserve University, School of Medicine, Cleveland, OH 44106-4938, USA.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Puchowicz
authors.forename: Kui
authors.initials: K
authors.lastname: Xu
authors.forename: Danielle
authors.initials: D
authors.lastname: Magness
authors.forename: Casey
authors.initials: C
authors.lastname: Miller
authors.forename: W David
authors.initials: WD
authors.lastname: Lust
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Kern
authors.forename: Joseph C
authors.initials: JC
authors.lastname: LaManna
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001812:Blood-Brain Barrier / Q000378:metabolism; D001813:Blood-Retinal Barrier / Q000378:metabolism*; D002540:Cerebral Cortex / Q000098:blood supply* / Q000378:metabolism; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism / Q000503:physiopathology*; D005947:Glucose / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000378:metabolism*; D012171:Retinal Vessels / Q000378:metabolism / Q000502:physiology
chemical_list: D001786:Blood Glucose; D005947:Glucose