195 OXIDATIVE METABOLISM AND UPTAKE OF KETONE BUDIES BY THE CEREBRAL CORTEX OF THE BABOON NEONATE

Net cerebral uptake of energy substrates was measured by repetitive arteriovenous sampling in 9 baboon neonates in the first 3 days of life. Catheters were placed in the aorta, left ventricular outflow tract, and in the superior sagittal sinus. Cardiac output and cerebral cortex blood flow were determined by the radioactive microsphere method. Glucose (G) uptake was 9.4±2.1 µM/min/kg body weight or 11.2±2.6 µM/min/100 g cerebral cortex. Cerebral uptake of alanine was detected in 4/4 animals, and of lactate in 3/9 animals. There was no net lactate release and no net uptake or release of glycerol. Infusion of Na DL-ßhydroxybutyrate (ßOHB) to steady state levels of 2-6 mM total KB (acetoacetate + D-ßOHB) did not alter G, lactate, or O2uptake. However, KB uptake was correlated in a linear fashion with arterial KB to levels of 8 mM.Although G/O2ratios less than 1 suggest that substrates other than glucose are utilized by the brain of the baboon neonate, cerebral KB uptake does not necessarily reflect oxidative metabolism of acetoacetate and D-ßOHB.