Korean J Med.  2001 Oct;61(4):430-438.

Inducibility of superoxide dismutases and metallothionein in the liver and kidney of mice by paraquat with age

Affiliations
  • 1Department of Pharmacology, Chosun University Medical School, Gwangju, Korea.
  • 2Department of Internal Medicine, Chosun University Medical School, Gwangju, Korea.
  • 3Department of General surgery, Chosun University Medical School, Gwangju, Korea.

Abstract

BACKGROUND: A number of theories have been proposed to explain the nature of aging process. Unfortunately, there is so far no theory that can completely explain all aging processes. In the present study, to investigate roles of inducibility of defense mechanisms by oxidative stress, cellular mRNA level of superoxide dismutases (SODs) and metallothionein (MT) as well as their inducibility by paraquat, an intracellular superoxide generator, was examined in the liver and kidney of the mice of aging process.
METHODS
The steady-state levels of SODs and MT mRNA and their induction by paraquat were determined by the RT-PCR assay in male mice of 4 ages, 1, 4, 8, and 12 months.
RESULTS
In the liver, the steady-state levels of Mn-SOD, Cu/Zn-SOD and MT mRNA increased until 8 months with age and decreased significantly at 12 months. Cu/Zn-SOD and MT mRNA were induced well by paraquat at all ages but Mn-SOD mRNA not at 12 months. In the kidney, their mRNA levels of Mn-SOD, Cu/Zn-SOD and MT increased with age. Mn-SOD mRNA was induced by paraquat only at 1 month but Cu/Zn-SOD mRNA not at all ages. On the other hand, MT mRNA was significantly induced by paraquat at all ages.
CONCLUSION
These results suggest that SODs and MT are differentially expressed and induced according to the age and organs. In addition, it is thought that the lack of induction of Mn-SOD by oxidative stress in both the liver and kidney may be one of causative factors in the aging process while Cu/Zn-SOD and MT in the liver and MT in the kidney may play protective roles in the aging process. It is therefore implicated that the tissue antioxidant/prooxidant balance could be one of determinants of mean life span.

Keyword

Aging; Reactive oxygen speices; Superoxide dismutases; Metallothionein; Paraquat

MeSH Terms

Aging
Animals
Defense Mechanisms
Hand
Humans
Kidney*
Liver*
Male
Metallothionein*
Mice*
Oxidative Stress
Paraquat*
RNA, Messenger
Superoxide Dismutase
Superoxides*
Metallothionein
Paraquat
RNA, Messenger
Superoxide Dismutase
Superoxides
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