Buffer capacity in the blood of the hemoglobinless Antarctic fish Chionodraco hamatus

Abstract

Blood acid-base homeostasis of the hemoglobinless Antarctic teleost Chionodraco hamatus was analyzed by measuring the titratable buffer capacity (β) and carbonic anhydrase (CA) activity in blood smaples. Results were compared with those obtained in the red-blooded temperate fish Anguilla anguilla. Data show that the titratable blood buffer capacity of icefish, in the range of red-blooded teleost species, was significantly higher than that of A. anguilla. Furthermore, plasma inorganic phosphate and reactive sulfhydryl content was significantly higher in the Antarctic species. No enzymatic activity of CA was detected in blood samples of Antarctic fish, suggesting the absence of a blood CA-isozyme.