Decreased glycolytic flux rate in the isolated perfused rat brain after pretreatment with 6-aminonicotinamide

Abstract

Cerebral energy metabolism was studied in the isolated perfused rat brain after 6-aminonicotinamide (6-AN; 35 mg/kg i.p.) administered to the intact animals 7 hrs before perfusion was started. The metabolic alterations in the isolated rat brains were such as reported for rat and mouse brain in vivo: Inhibition of 6-phosphogluconate dehydrogenase was followed by an accumulation of 6-phosphogluconate, leading to a decreased activity of glucosephosphate isomerse. This was reflected by increased levels of glucose and glucose 6-phosphate and decreased levels of fructose 6-phosphate, pyruvate and lactate. Since the concentration of lactate in the perfusate of the isolated brain was also lowered, 6-AN must have reduced the glycolytic flux rate.