title: Age-related quantitative changes in enzyme activities of rat brain.
abstract: The patterns of brain enzymes linked to energy metabolism have been determined in rats aged between 3 and 21 months and compared to those of the developing brain as an estimate of the senescent energy capacity of this organ. During aging, pyruvate kinase increases, pointing towards an enhancement of the glucose-dependence of this organ. However, NAD-isocitrate dehydrogenase declines, suggesting a reduction of Krebs cycle activity in the aged rat brain. An increase in cytoplasmic NAD-malate dehydrogenase found during aging could provide an alternative mechanism of NAD recovery.
mesh_terms: D000375:Aging; D000818:Animals; D001921:Brain / Q000201:enzymology / Q000254:growth & development*; D002950:Citrate (si)-Synthase / Q000378:metabolism*; D002952:Citric Acid Cycle; D005260:Female; D005969:Glutamate Dehydrogenase / Q000378:metabolism*; D006019:Glycolysis; D007521:Isocitrate Dehydrogenase / Q000378:metabolism*; D008291:Malate Dehydrogenase / Q000378:metabolism*; D008297:Male; D008928:Mitochondria / Q000201:enzymology; D007652:Oxo-Acid-Lyases / Q000378:metabolism*; D011770:Pyruvate Kinase / Q000378:metabolism*; D051381:Rats; D013385:Succinate Dehydrogenase / Q000378:metabolism*
chemical_list: D008291:Malate Dehydrogenase; D007521:Isocitrate Dehydrogenase; D013385:Succinate Dehydrogenase; D005969:Glutamate Dehydrogenase; D002950:Citrate (si)-Synthase; D011770:Pyruvate Kinase; D007652:Oxo-Acid-Lyases