Organ lactic dehydrogenase in altitude-acclimatized rats

725-728. 1968.-Continuous exposure of adult male albino rats to a simulated altitude of 18,000 ft for 2-4 months had no effect on the lactic dehydrogenase activity or isozyme pattern of brain, heart, liver, diaphragm, and gastrocnemius muscle. Daily injections of lactate or pyruvate, in doses sufficient to raise their concentration in body water above the highest reported in exercising ischemic muscle, were likewise without effect on the activity and isozyme pattern of the enzyme. It is concluded that changes in lactic dehydrogenase play no role in the process of altitude acclimatization in the albino rat, isozymes; altitude acclimatization; enzyme induction W HEN SEA LEVEL RESIDENTS go to high altitude they usually experience a brief episode of acute mountain sickness, followed by a slowly developing increase in tolerance referred to as acclimatization. The physiologi