REVERSAL OF PORTACAVAL SHUNTING NORMALIZES BRAIN ENERGY-CONSUMPTION IN MOST BRAIN STRUCTURES

The cerebral metabolic rate of glucose consumption (CMR(Glc)) was meas ured throughout brains of rats with 1) portacaval shunts created for 2 wk, followed by restoration of normal blood circulation for 2 wk; 2) portacaval shunts created for 2 wk, followed by a sham operation and 2 wk of recovery; 3) two sham operations, each with 2 wk of recovery ti mes. Portacaval-shunted rats had diminished CMR(Glc) (decreases of 7-2 3%) throughout the brain in agreement with previous studies. After res toration of normal liver blood flow, the CMR(Glc) of most structures r eturned to near-normal values, although a few structures, notably the hippocampus, remained 11-13% lower. These data suggest that the conseq uences of portacaval shunting to brain energy metabolism can be marked ly improved, if not completely reversed, by restoring the normal patte rn of blood flow to an otherwise healthy liver. Other metabolic and ph ysical data collected (liver weight, liver-to-body weight, plasma ammo nia) returned to normal except plasma glucose concentrations, which re mained lower by 11%, suggesting a persistent, albeit mild, defect in g lucose homeostasis.