[Trace reactions in tissue metabolism to changes in the ambient temperature of Rana ridibunda Pall. frogs].

Rather high Q10 (Q10 greater than 2) of brain and skeletal muscle tissue respiration (incubation at 13 degrees and 23 degrees C) was observed in cold (7 degrees C) and warm (23 degrees C) acclimated frogs. The transfer of animals from cold to warm environment caused a significant decrease in Q10 within 1.4-24 hrs whereas no change in Q10 followed the reverse transfer: 24-hr cooling of warm-acclimated frogs. This trace reaction: the Q10 reduction of brain tissue respiration, is absent in 1 hour after the transfer to warm environment, and gradually appears within 24 hrs. In an hour after rewarming, Q10 of skeletal muscle tissues sharply increases (1.87 to 2.27), then a 6 to 18-hr plateau follows and by the 24th hour the Q10 is reduced to 1.78. These events are supposed to be based on a discordance in the time of membrane permeability and enzyme activity changes which result in cellular alterations in enzyme/substrate ratio.