Short-term CR decreases cardiac mitochondrial oxidant production but increases carbonyl content

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology Vol. 286; no. 2; pp. 254 - R259
• Main Authors: Judge, Sharon, Judge, Andrew, Grune, Tilman, Leeuwenburgh, Christiaan
• Format: Journal Article
• Language: English
• Published: United States 01.02.2004
• Subjects: Animals; Body Weight; Caloric Restriction; Cysteine Endopeptidases - metabolism; Heart - anatomy & histology; Hydrogen Peroxide - metabolism; Male; Mitochondria, Heart - enzymology; Mitochondria, Heart - metabolism; Mitochondrial Proteins - metabolism; Multienzyme Complexes - metabolism; Organ Size; Oxidation-Reduction; Oxidoreductases - biosynthesis; Proteasome Endopeptidase Complex; Rats; Rats, Inbred F344
• ISSN: 0363-6119; 1522-1490
• DOI: 10.1152/ajpregu.00502.2003

1 Biochemistry of Aging Laboratory, 2 Center for Exercise Science, University of Florida, Gainesville, Florida 32611; and 3 Institute of Environmental Medical Research, Molecular Ageing Research, 40225 Dusseldorf, Germany Submitted 20 September 2003 ; accepted in final form 27 October 2003 ABSTRACT Lifelong caloric restriction (CR) reduces the rate of mitochondrial oxidant production and the accumulation of oxidized proteins and prevents some of the age-associated decline in 20S proteasome activity. However, few studies have investigated how rapidly the beneficial effects of CR take place. We investigated whether 2 mo of CR in 6-mo-old rats would be of sufficient duration to elicit these beneficial changes. Mitochondrial oxidant production was significantly diminished in the CR rats compared with the ad libitum-fed animals. Short-term CR also caused a significant decrease in mitochondrial superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities, but there were no differences in cytosolic SOD and GPX activities, whereas mitochondrial and cytosolic catalase (CAT) activity was increased with CR. However, protein carbonyl content was significantly elevated in both the mitochondrial and cytosolic fractions from CR rats. Of the three major 20S proteasome activities (chymotrypsin-like, trypsin-like, and peptidylglutamyl-peptide hydrolase), the peptidylglutamyl-peptide hydrolase activity was significantly elevated in the CR animals, possibly because of the fact that there were more oxidized proteins to be degraded. Although fewer oxidants were produced in the CR animals, it is possible that the ability to scavenge oxidants was transiently suppressed because of the reduction in mitochondrial antioxidant enzyme activities, which may explain the observed increases in carbonyl content. hydrogen peroxide production; superoxide dismutase; glutathione peroxidase; protein oxidation; 20S proteasome activity Address for reprint requests and other correspondence: C. Leeuwenburgh, Univ. of Florida, Biochemistry of Aging Laboratory, P. O. Box 118206, Gainesville, FL 32611 (E-mail: cleeuwen{at}ufl.edu ).