Effects of Acute, Submaximal Exercise on Skeletal Muscle Vitamin E

Abstract

Vitamin E is the major lipid soluble anti-oxidant and may play an important protective role against free radicals produced during exercise. The purpose of this study was to determine the effect of a submaximal exercise bout on vitamin E levels in selected tissues. Five week- old lean, female Zucker rats were randomly divided into sedentary and run groups. At least 4 days following a maximal VO₂ test, the run group (n = 7) ran on a treadmill at 70.3 ± 1.5% VO₂ max for 34-42 minutes. Duration was varied according to body weight to keep total work constant. Immediately post-exercise, animals were decapitated, exsanguinated and the quadriceps (red and white vastus lateralis), liver and heart quickly excised and stored under liquid nitrogen until analyzed. Lipids were extracted in heptane and alpha-tocopherol levels determined by reverse-phase HPLC with electrochemical detection. Quadriceps vitamin-E levels declined post-exercise 30% compared to sedentary controls. Specifically, in the red quadriceps from 37 ± 2 to 26 ± 2(n = 7, p < 0.01), and in the white quadriceps from 22 ± 2 to 16 ± 2(p< 0.05) nmol/g wet weight. No change in vitamin E content was noted for either heart (113 ± 6 vs. 110 ± 7, p> 0.05) or liver (68 ± 6 vs. 78 ± 5, p> 0.05). It is concluded that a single bout of submaximal treadmill running can result in a significant depletion of vitamin E in skeletal muscle.

Key Words:

• Vitamin E
• exercise
• skeletal muscle