Reversal of portacaval shunting normalizes brain energy consumption in most brain structures

The cerebral metabolic rate of glucose consumption (CMRGlc) was measured 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 times. Portacaval-shunted rats had diminished CMRGlc (decreases of 7-23%) throughout the brain in agreement with previous studies. After restoration of normal liver blood flow, the CMRGlc of most structures returned to near-normal values, although a few structures, notably the hippocampus, remained 11-13% lower. These data suggest that the consequences of portacaval shunting to brain energy metabolism can be markedly improved, if not completely reversed, by restoring the normal pattern of blood flow to an otherwise healthy liver. Other metabolic and physical data collected (liver weight, liver-to-body weight, plasma ammonia) returned to normal except plasma glucose concentrations, which remained lower by 11%, suggesting a persistent, albeit mild, defect in glucose homeostasis.