Cerebral blood flow and metabolic rate of oxygen, glucose, lactate, pyruvate, ketone bodies and amino acids.

The cerebral blood flow (CBF) and cerebral metabolic rate (CMR) of oxygen, glucose, lactate, pyruvate, ketone bodies and 24 amino acids were examined in 12 patients with presenile dementia and in seven with normal-pressure hydrocephalus. Both groups of patients showed significantly lower values of CBF and cerebral uptake of oxygen and glucose than 10 healthy subjects examined concurrently. The values decreased roughly in proportion to the degree of clinical deterioration. Furthermore, the patients exhibited a significant release of lactate and pyruvate. A positive correlation was found between CMR and arterial concentration of ketone bodies. The group with presenile dementia showed no uptake of amino acids, but a significant release of phenylalanine; in addition, CMR of alanine and threonine was significantly lower than in the healthy subjects. These findings suggest a cerebral catabolic state. Four patients with normal-pressure hydrocephalus were also studied after shunt operations. All showed an increase of CMR glucose and a decrease of CMR ketone bodies, acetoacetate as well as D-beta-hydroxybutyrate, which could not be attributed to a consistent decrease of arterial levels of ketone bodies.