AJP - Regulatory, Integrative and Comparative Physiology, Vol 250, Issue 1 127-R136, Copyright © 1986 by American Physiological Society
Glucose transport and metabolism in the brain
P. J. Robinson and S. I. Rapoport
A model is proposed for the uptake and metabolism of cold and radiotracer
glucose that takes into account the concentration profiles of the cold and
tracer glucose as they pass through the capillary bed of the brain. The
model incorporates capillary blood flow, nonlinear transport between blood
and brain, and Michaelis-Menten kinetics for incorporation of glucose into
the brain metabolic pool. Analytical equations are derived for the
conditions of normoglycemia and hypoglycemia. In normoglycemia, cold
glucose uptake is determined solely by metabolic demand and is relatively
independent of fluctuations in plasma glucose levels. At lower glucose
levels, transport of glucose across the blood-brain barrier becomes a
progressively more important factor in determining uptake. Uptake of
radiotracer glucose depends primarily on transport parameters. Functional
heterogeneity of the capillary bed is considered both in relation to
glucose uptake and parameter estimation.
