Krebs cycle enzymes from livers of old mice are differentially regulated by caloric restriction
- 31 August 2004
- journal article
- Published by Elsevier BV in Experimental Gerontology
- Vol. 39 (8), 1145-1154
- https://doi.org/10.1016/j.exger.2004.04.009
Abstract
Krebs cycle enzyme activities and levels of five metabolites were determined from livers of old mice (30 months) maintained either on control or on long-term caloric restriction (CR) diets (28 months). In CR mice, the cycle was divided into two major blocks, the first containing citrate synthase, aconitase and NAD-dependent isocitrate dehydrogenase which showed decreased activities, while the second block, containing the remaining enzymes, displayed increased activity (except for fumarase, which was unchanged). CR also resulted in decreased levels of citrate, glutamate and α-ketoglutarate, increased levels of malate, and unchanged levels of aspartate. The α-ketoglutarate/glutamate and malate/α-ketoglutarate ratios were higher in CR, in parallel with previously reported increases with CR in pyruvate carboxylase activity and glucagon levels, respectively. The results indicate that long-term CR induces a differential regulation of Krebs cycle in old mice and this regulation may be the result of changes in gene expression levels, as well as a complex interplay between enzymes, hormones and other effectors. Truncation of Krebs cycle by CR may be an important adaptation to utilize available substrates for the gluconeogenesis necessary to sustain glycolytic tissues, such as brain.Keywords
This publication has 42 references indexed in Scilit:
- Selectivity of protein oxidative damage during aging in Drosophila melanogasterBiochemical Journal, 2001
- Genomic profiling of short- and long-term caloric restriction effects in the liver of aging miceProceedings of the National Academy of Sciences, 2001
- Caloric restriction alters the feeding response of key metabolic enzyme genesMechanisms of Ageing and Development, 2001
- Deviant energetic metabolism of glycolytic cancer cellsBiochimie, 1992
- Ca2+ As a Second Messenger within Mitochondria of the Heart and other TissuesAnnual Review of Physiology, 1990
- The calcium sensitive dehydrogenases of vertebrate mitochondriaCell Calcium, 1986
- Some structural and regulatory aspects of citrate synthaseInternational Journal of Biochemistry, 1984
- Selective inactivation of the transacylase components of the 2-oxo acid dehydrogenase multienzyme complexes of Escherichia coliBiochemical Journal, 1976
- [18] Mitochondrial l-malate dehydrogenase of beef heartMethods in enzymology, 1969
- [13] Succinate thiokinase from pig heartPublished by Elsevier BV ,1969