Cellular and Tisular Adaptation to Hypoxia

摘要

The following adaptive mechanisms to chronic hypoxia are under investigation: (1) Diminution in cell size, (2)Larger P/O ratios in vivo and, (3) Increased anaerobic energy production. The number of cells per unit weight of tissue (red muscle, white muscle, heart, brain and liver) seems to be the same in sea level and high altitude guinea pigs, as evidenced by DNA content. In view of the increased extracellular volume reported in high altitude animals the cell size must be smaller. Improved methods are described. Methods developed for the determination of P/O ratios in vivo are described and discussed. The concentrations of L-alpha glycerophosphate and L-Lactate were determined in red and white muscle, heart and liver in sea level guinea pigs under 'aerobic' and 'ischemic' conditions. Both compounds accumulate in the latter condition to different extent in the various tissues studied. Methods and equipment are described. The classical spectrophotometric procedure for myoglobin determination in the presence of hemoglobin is not applicable to guinea pigs. Conclusive evidence is presented to the effect. A simple method for myoglobin isolation is described. Methods for qualitative and quantitative gas liquid chromatographic analysis of the Krebs cycle acids are described. Contemplated future developments are discussed in view of the results obtained. (Author)