The activity of oxidative enzymes of the Krebs cycle was examined in white rats during hypokinesia. On hypokinesia day 7 the cytosol activity of NAD-dependent isocitrate dehydrogenase (ICDH) increased and that of malic-enzyme decreased. On hypokinesia days 30 and 45 the activity of succinate dehydrogenase (SDH) and alpha-ketoglutarate dehydrogenase (alpha-KGDH) decreased, that of cytoplasmatic malate dehydrogenases (MDH) slightly increased, and that of NADP ICDH declined. On hypokinesia day 60 the total activity of mitochondrial dehydrogenases reduced due to a low protein content of the mitochondrial fraction, whereas the specific activity either remained unchanged (ICDH, NAD MDH, alpha-KGDH) or increased (SDH, NADP MDH). On recovery day 25 only the activity of mitochondrial NAD-dependent malate and isocitrate dehydrogenases returned to normal.
Animals Citric Acid Cycle