Abstract
Afferent discharges was recorded from nerve filaments dissected from the hepatic branch of the vagus nerve in the guinea pig in situ. A significant decrease in the discharge rate was observed following the administration of D-glucose into the portal vein, but not after the administration of D-mannose, D-fructose, D-galactose, L-glucose, D-xylose or D-arabinose. The mean discharge rate of these fibers was inversely related to the concentration of glucose in the portal blood. The existence of D-glucose sensors in the liver which monitor the glucose concentration of portal blood is suggested.