Effect of Short Term Hypobaric Hypoxia on Myoglobin Contents in Rat Skeletal and Cardiac Muscles

Effects of short term hypobaric hypoxia on myoglobin (Mb) content and enzyme activities in skeletal and cardiac muscles were investigated. Eight male Sprague-Dawley rats (120-150g) were exposed to a simulated altitude of 6,000m (0.46 atm) for 2 hr per day for 11 days. The results obtained were as follows: 1. Mb contents in the white part of m. vastus lateralis, m. soleus and cardiac muscle were higher in rats exposed to hypoxia than in control rats. However, there were no significant difference between contorol and hypoxic group. 2. There were no significant changes in citrate synthase activity in skeletal and cardiac muscle exposed to hypoxia. 3. No significant changes in lactate dehydrogenase were observed in hypoxic group. These results suggest that 11 days exposure to hypobaric hypoxia was too short to stimulate the increase of Mb content and enzyme activity in skeletal and cardiac muscle