Effect of acclimation temperature on intraerythrocytic acid-base balance and nucleoside triphosphates in the carp, Cyprinus carpio.

In carp acclimated to 20 degrees C or 10 degrees C intraerythrocytic pH (pHi) and plasma pH (pHe) were determined in vitro after equilibration with CO2 in either O2 or N2. ATP and GTP were determined with an enzymatic assay described in detail. The relationship between pHi, pHe and oxygen saturation was not affected by the acclimation temperature and was (pHi-6.10) = (0.853-0.159 X S) X (pHe-6.21) There was a slight but significant decrease in ATP at 20 degrees C. Apparent buffer values were affected by oxygenation and temperature. It is concluded from the recalculated CO2 Bohr factor and from the temperature effect on the buffer value that carp hemoglobin forms carbamate which decreases at a higher temperature. These changes in ATP and carbamate can partly account for the increase in whole blood oxygen affinity in carp acclimated at a high temperature.