1999 Volume 27 Issue 3 Pages 151-159
To evaluate the effects of voluntary resistance exercise training on mitochondrial heme biosynthesis in the liver, we trained adult male Sprague-Dawley rats for 4 or 8 weeks to climb a wire-mesh tower (∅20cm×200cm), and then measured δ-aminolevulinic acid synthetase (ALAS) activity, the rate-limiting enzyme of heme synthesis, and cytochrome c content in their liver. The activity of citrate synthase in the skeletal muscle was also determined to establish whether the training protocol had any aerobic effect. Resistance training resulted in significant increases (p<0.05) in citrate synthase activities in gastrocnemius and forearm muscles, whereas ALAS activity and cytochrome c content in the liver of rats trained for 4 and 8 weeks were the same as those of corresponding sedentary rats. The relative weight of forearm muscle to body mass was significantly greater (p<0.05) in the training group than in the sedentary group. These results suggest that voluntary resistance exercise does not accelerate hepatic heme biosynthesis in spite of increasing aerobic capacity in the skeletal muscles.
