Cerebrovascular Flow and Glucose Transport in the Hydrocephalic Rat

This study evaluates regional cerebral perfusion flow and unidirectional glucose transport across the cerebral capillar in hydrocephalic rats. Perfusion flow and glucose influx were measured with 99mTc-ECD (Dupont Corp.) and 14C-(d)-Glucose, respectively. Perfusion flows for the control and hydrocephalic groups were 1.77ml/min per g and 1.53ml/min per g, respectively. The hydrocephalic perfusion flow was significantly lower than the control flow (P < .05). Maximal influx of glucose (Vmax) for the control group was 2.74 μm/min per g. The Vmax for the hydrocephalic group was 3.19 μm/min per g. Substrate concentration at half maximal transport (Km) was 8.02 mM for the controls and 11.5 mM for the hydrocephalies. There was no substantial difference between control and hydrocephalic groups for these kinetic parameters. These data suggest that reported changes in cerebral metabolism in hydrocephalus are due to derangements in utilization rather than to facilitated diffusion of glucose across the blood brain barrier.