Journal article
Thiol supplementation in aged animals alters antioxidant enzyme activity after heat stress
Journal of applied physiology (1985), Vol.99(6), pp.2271-2277
2005
DOI: 10.1152/japplphysiol.00412.2005
PMID: 16099896
Abstract
Declines in oxidative and thermal stress tolerance are well documented in aging systems. It is thought that these alterations are due in part to reductions in antioxidant defenses. Although intracellular thiols are major redox buffers, their role in maintaining redox homeostasis is not completely understood, particularly during aging, where the reliance on antioxidant enzymes and proteins may be altered. To determine whether thiol supplementation improved the antioxidant enzyme profile of aged animals after heat stress, young and old Fischer 344 rats were treated with N-acetylcysteine (NAC; 4 mmol/kg ip) 2 h before heat stress. Liver tissue was collected before and 0, 30, and 60 min after heat stress. Aging was associated with a significant decline in tissue cysteine and glutathione (GSH) levels. There was also an age-related decrease in copper-zinc superoxide dismutase activity. Heat stress did not alter liver GSH, glutathione disulfide, or antioxidant enzyme activity. With NAC treatment, old animals took up more cysteine than young animals as reflected in an increase in liver GSH and a corresponding decrease in glutamate cysteine ligase activity. Catalase activity increased after NAC treatment in both age groups. Copper-zinc superoxide dismutase activity did not change with heat stress or drug treatment, whereas manganese superoxide dismutase activity was increased in old animals only. These data indicate that GSH synthesis is substrate limited in old animals. Furthermore, aged animals were characterized by large fluctuations in antioxidant enzyme balance after NAC treatment, suggesting a lack of fine control over these enzymes that may leave aged animals susceptible to subsequent stress.
Details
- Title: Subtitle
- Thiol supplementation in aged animals alters antioxidant enzyme activity after heat stress
- Creators
- Joanna P MORRISON - Integrative Physiology Laboratory, Department of Exercise Science, Holden Comprehensive Cancer Center, The University of Iowa, Iowa City, Iowa, United StatesMitchell C COLEMAN - Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, The University of Iowa, Iowa City, Iowa, United StatesElizabeth S AUNAN - Integrative Physiology Laboratory, Department of Exercise Science, Holden Comprehensive Cancer Center, The University of Iowa, Iowa City, Iowa, United StatesSusan A WALSH - Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, The University of Iowa, Iowa City, Iowa, United StatesDouglas R SPITZ - Free Radical and Radiation Biology Program, Department of Radiation Oncology, Holden Comprehensive Cancer Center, The University of Iowa, Iowa City, Iowa, United StatesKevin C KREGEL - Integrative Physiology Laboratory, Department of Exercise Science, Holden Comprehensive Cancer Center, The University of Iowa, Iowa City, Iowa, United States
- Resource Type
- Journal article
- Publication Details
- Journal of applied physiology (1985), Vol.99(6), pp.2271-2277
- Publisher
- American Physiological Society; Bethesda, MD
- DOI
- 10.1152/japplphysiol.00412.2005
- PMID
- 16099896
- ISSN
- 8750-7587
- eISSN
- 1522-1601
- Language
- English
- Date published
- 2005
- Academic Unit
- Radiology; Pathology; Orthopedics and Rehabilitation; Radiation Oncology; Provost Office Administration; Health and Human Physiology
- Record Identifier
- 9984024518302771
Metrics
16 Record Views