Differential increase in cerebral cortical glucose oxidative metabolism during rat postnatal development is greater in vivo than in vitro

• Published in: Brain research 2001-01, Vol.888 (2), p.193-202
• Main Authors: Novotny, Edward J., Ariyan, Cristopher, Mason, Graeme F., O’Reilly, John, Haddad, Gabriel G., Behar, Kevin L.
• Format: Article
• Language: English
• Subjects: 13C isotopes; Aging - metabolism; Animals; Biological and medical sciences; Blood Glucose - drug effects; Blood Glucose - metabolism; Carbon Isotopes; Cerebral Cortex - metabolism; Cerebral development; Citric Acid Cycle - physiology; Development. Senescence. Regeneration. Transplantation; Female; Fundamental and applied biological sciences. Psychology; Glucose - administration & dosage; Glucose - metabolism; Glutamate; Glycolysis; In Vitro Techniques; Infusions, Intravenous; Lactic Acid - blood; Male; Mitochondria - metabolism; Nuclear magnetic resonance spectroscopy; Oxidation-Reduction; Oxygen consumption; Rats; Rats, Sprague-Dawley; Tricarboxylic acid cycle; Vertebrates: nervous system and sense organs
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/S0006-8993(00)03051-1

The steady-state rate of glucose oxidation through the mitochondrial TCA cycle ( V TCA) was measured in acid extracts of 10- and 30-day-old cerebral cortex of rats receiving [1- 13C]glucose intravenously and in neocortical slices superfused in vitro with the same isotope. TCA cycle flux was determined for each age group based on metabolic modeling analysis of the isotopic turnover of cortical glutamate and lactate. The sensitivity of the calculated rates to assumed parameters in the model were also assessed. Between 10 and 30 postnatal days, V TCA increased by 4.3-fold (from 0.46 to 2.0 μmol g −1 min −1) in the cortex in vivo, whereas only a 2-fold (from 0.17 to 0.34 μmol g −1 min −1) increase was observed in neocortical slices. The much greater increase in glucose oxidative metabolism of the cortex measured in vivo over that measured in vitro as the cortex matures suggests that function-related energy demands increase during development, a process that is deficient in the slice as a result of deafferentiation and other mechanisms.