Authors
Barja G. Cadenas S. Rojas C. Lopez-Torres M. Perez-Campo R.
Institution
Department of Animal Biology-II (Animal Physiology), Faculty of Biology,
Complutense University, Madrid, Spain.
Title
A decrease of free radical
production near critical targets as a cause of maximum longevity in animals.
Source
Comparative Biochemistry & Physiology. Biochemistry & Molecular Biology.
108(4):501-12, 1994 Aug.
Abstract
A comprehensive study was performed on the brains of various vertebrate
species showing different life energy potentials in order to find out if
free radicals are important determinants of
species-specific maximum life span. Brain superoxide dismutase, catalase,
Se-dependent and independent GSH-peroxidases, GSH-reductase, and ascorbic
acid showed significant inverse correlations with maximum longevity, whereas
GSH, uric acid, GSSG/GSH, in vitro peroxidation (thiobarbituric acid test),
and malondialdehyde (measured by HPLC), did not correlate with maximum life
span. Superoxide dismutase, catalase, GSH-peroxidase, GSH and ascorbate
results agree with those previously reported in various independent works
using different animal species. GSSG/GSH, and true malondialdehyde (HPLC)
results are reported for the first time in relation to maximum longevity. The
results suggest that longevous species simultaneously show low antioxidant
concentrations and low levels of in vivo free
radical production (a low free
radical turnover) in their tissues. The
"free radical production hypothesis of
aging" is proposed: a decrease in oxygen
radical production per unit of O2 consumption near critical
DNA targets (mitochondria or nucleus) increases the maximum life span of
extraordinarily long-lived species like birds, primates, and man.
Free radical production near these DNA
sites would be a main factor responsible for aging in all the species, in
those following Pearl's (Rubner's) metabolic rule as well as in those not
following it.