[Oxidative processes in carp liver mitochondria during adaptation to changes of CO2 concentration in water]

Two-years-old carps (Cyprinus carpio L.) were kept for 1,3 and 7 days in the medium with different concentrations of CO2. In the fish liver mitochondria the rate of CO2 uptake (state 4p) and phosphorylation (state 3) as well as the value of the respiratory control and the activity of cytochrome oxidase and succinate dehydrogenase undergo significant changes. In fishes which were in the medium with 0.4 mM CO2 for a day the cytochrome oxidase activity in the mitochondria increases sharply, but that of succinate dehydrogenase decreases. The lowest activity of both enzymes is fixed in the carp liver mitochondria during the three-day adaptation to such a medium. In the first day in the medium with 0.4 mM CO2 the rate of O2 uptake by the mitochondria in the states 4p and 3 rises. Seven days later the values of all the studied indices in the mitochondria reach gradually the control level. In the medium with 0.8 mM CO2 the oxidative processes in the mitochondria are more inhibited than in water with 0.4 mM CO2.