Abstract

The purpose of this study was to investigate the effect of zinc deficiency on the free radical generation and the free radical elimination in exercised mice. 16 weanling mice were fed a zinc-deficient diet containing 1.6 ppm zinc, and the other 32 in two control groups were pair-fed or fed ad libitum a zinc-adequate diet containing 51.6 ppm zinc. Half of each group received an exercise training programme consisting of swimming for 60 min per day in deionized water. The diets and the exercise programme persisted for 6 wks. Free radicals in liver were directly detected by electron spin resonance (ESR) techniques and the zinc, copper, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) were also determined. The results showed that (1) exercise training increased the requirement of zinc; (2) zinc deficiency would lead to an increased free radical generation, lipid peroxidation and a decreased hepatic CUZn-SOD activity in both sedentary and exercised mice; (3) exercise training had no effects on the MDA production in mice fed ad libitum the zinc-adequate diet, but further increased the hepatic mitochondrial MDA formation in zinc-deficient animals; (4) exercise training did strengthen the free radical elimination but zinc deficiency would abolish the exercise-induced adaptation; (5) additionally, it could also be concluded from this study that food restriction should not be encouraged in exercised subjects. Verf.-Referat