[Changes in plasma LDH-isozyme in rats during hypoxia and its recovery stage]

Rats were placed in an air-tight glass dome connected to a spirometer, into which nitrogen gas was introduced gradually, to achieve oxygen concentration of about 10%. The animals gradually exhibited dyspnea, and became apneic after about 30 min. Most of the rats in this stage died after the sampling. A different group of rats were returned to the room air from the apneic stage with hypoxia, and were used for the study on the recovery stage. Blood gas analysis revealed severe acidosis and hypoxemia during the apneic stage, while PO2, O2 CT, and O2SAT increased rapidly and significantly during the recovery stage. pH was unchanged between the apneic and recovery stages. During the apneic stage, plasma LDH-zymogram was similar to that of the liver taken as the control. However, after returning from hypoxia, the LDH-isozyme patterns quickly approached that of the heart muscle with increasing LDH1 and LDH2. During hypoxia, the changes of arterial oxygen content with alteration of blood flow in the organs, brought direct effects upon the blood isozyme patterns.