Fig. 5. Rates of oxygen consumption by isolated hepatocytes from L. kempi (A) and P. brachycephalum (B), measured after exposure to media of different pH and P_CO2. Control values at the respective pHe were determined after incubation of cells without cycloheximide. To measure the decrease of oxygen consumption rate induced by inhibition of protein biosynthesis, cells were incubated for 60 min with 35.5 µmol l^-1 cycloheximide prior to analysis of metabolic rate. ^aOxygen consumption rates significantly different from the respective control value at pHe 7.90 or pHe 6.50; ^boxygen consumption rates significantly different from the respective cycloheximide-inhibited value at pHe 7.90 (significant differences within normalized data were identified using the Mann-Whitney rank sum test; all results were confirmed by an additional analysis of original data with the Student's t-test for paired samples). Values are means ± S.D., N=6 for both species.