A STUDY IN MAN OF CEREBRAL BLOOD FLOW AND CEREBRAL GLUCOSE, LACTATE AND PYRUVATE METABOLISM BEFORE AND AFTER EATING*

Abstract

Determination of cerebral blood flow and brain carbohydrate uptake before and after a test meal were studied. During the time when the arterial levels of glucose, lactate and pyruvate were rising, the brain took up larger quantities of these carbohydrates. As the peak blood concentration of glucose was reached the uptake returned to the control values, and during the time when the level of the substances was falling rapidly, uptake of glucose by the brain was reduced to below the control value. The fact that glucose and lactate uptake are not related to their absolute arterial level is compatible with the thesis that the arterial level of these substances does not control their rate of utilization by the brain. Brain pyruvate extraction and calculated consumption were correlated directly with the arterial level of pyruvate.