Carbohydrate catabolism in cerebral cortex

Abstract

The Pasteur effect is defined as the effect of oxygen in reducing carbohydrate catabolism and in diminishing or suppressing the accumulation of anaerobic cleavage products. The symbols [image] and [image] are introduced to denote the rates of destruction of hexose in oxygen and in N respectively. These rates are measured as the number of ul of hexose expressed as a gas at N. T. P. destroyed by 1 mg. dry weight of tissue per hour. The Pasteur effect is operating when Q[image] is numerically less than [image]. It is possible to calculate [image] and [image] from measurements of the resplration and glycolysis in slices of cerebral cortex. It is shown that.[image].[image] thus calculated is numerically less than Q^*. These calculations are confirmed by direct measurement of the rate of destruction of glucose by slices of brain cortex. The aerobic rate of destruction of glucose is much less than the anaerobic. The Pasteur effect is thus directly demonstrated in the cerebral cortex of the rabbit. Further, the addition of KCl (one of the so-called inhibitors of the Pasteur effect) raises the aerobic destruction of sugar to the anaerobic level.