Effect of hemodilution on regional cerebral blood flow during chronic hyperglycemia in rats.
Regional cerebral blood flow decreases during chronic hyperglycemia, a condition frequently associated with elevated hematocrit. To test the hypothesis that an elevated hematocrit is responsible for the reduced regional cerebral blood flow during chronic hyperglycemia, I used isovolemic hemodilution to normalize the hematocrit in seven normoglycemic and seven streptozotocin-treated (hyperglycemic) rats. Regional cerebral blood flow was measured in 28 awake, restrained rats (14 normoglycemic and 14 hyperglycemic) using [14C]iodoantipyrine and dissection of 17 brain regions. Hemodilution lowered the hematocrit by 6 units (13%) and increased the average cerebral blood flow by 14%. Chronic hyperglycemia did not elevate the hematocrit, but it decreased the average cerebral blood flow by 12% and that in nine nontelencephalic brain regions by 17%. This effect was independent of changes in hematocrit caused by hemodilution. The reduced regional cerebral blood flow during chronic hyperglycemia is not caused by elevated hematocrit.
Duckrow
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Department of Medicine (Division of Neurology), Milton S. Hershey Medical Center, Pennsylvania State University, Hershey 17033.
D000818:Animals; D001921:Brain / Q000098:blood supply*; D005260:Female; D006400:Hematocrit; D006438:Hemodilution; D006943:Hyperglycemia / Q000503:physiopathology*; D009928:Organ Specificity; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D012039:Regional Blood Flow