1. It having previously been shown that the injection of the non-metabolizable sugar, 3-methylglucose, into normal rats provokes the release of adrenaline with consequent hyperglycaemia, the effect of 3-methylglucose upon the metabolism of glucose was investigated. In rats, whose adrenal glands had been denervated by transplantation, 3-methylglucose reduced the oxidation of glucose by 46%. A reduction of this magnitude cannot be accounted for unless the oxidation of glucose by the brain is depressed.