Rapid steady-state analysis of blood-brain glucose transfer in rat.
A new kinetic analysis of blood-brain glucose transport is described, based on a steady-state model that takes account of cerebral blood flow, mean capillary glucose concentration, and cerebral metabolic rate. The maximal rate (Tmax) and half-saturation constant (Km) of glucose transport from blood to brain were determined in rats by measuring the rate of blood-to-brain glucose transfer at different blood glucose concentrations. Each determination lasted 20 seconds. For whole-brain, Tmax and Km averaged 258 +/- 33 (S.E.) mumol L(100 g)-1 min-1 and 5.9 +/- 1.6 (S.E.) mmol 1-1, respectively. The regional variations were insignificant. The new approach permits kinetic parameters to be measured locally in brain in rapidly changing functional states.
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001812:Blood-Brain Barrier; D001921:Brain / Q000378:metabolism*; D002560:Cerebrovascular Circulation; D005947:Glucose / Q000008:administration & dosage / Q000378:metabolism*; D007328:Insulin / Q000008:administration & dosage; D007700:Kinetics; D008297:Male; D008954:Models, Biological; D051381:Rats
D001786:Blood Glucose; D007328:Insulin; D005947:Glucose