Acid-base balance in plasmatic, pericardial and peritoneal fluids in 2 species of amphibians.

The carbonic acid-base balance and the concentrations of Na and Cl were studied in 3 fluids, plasmatic, pericardial and peritoneal, sampled from 2 species of amphibians: Pleurodeles waltl and Xenopus laevis. In Pleurodeles the pericardial and peritoneal fluids are in a state of marked metabolic alkalosis, the carbonate alkalinity being up to 10 times higher in the serosal fluids than in the plasma, whereas PCO2's are very close in the 3 fluids. The Cl concentration is markedly lower in the serosal fluids than in the plasma. In Xenopus, the metabolic alkalosis of the serosal fluids also exists, but to a much lower extent than in Pleurodeles. These observations lead to further researches in the field of morphometry, physicochemistry and physiology.