Effects of isotonic swelling on the intracellular Bohr factor and the oxygen affinity of trout and carp blood.

Blood samples from carp and trout were exposed to overnight tonometry in the presence of noradrenaline to obtain isosmotic cell swelling. The intracellular fixed acid Bohr factor (Φfa(i)) were then measured and compared to the values for unswollen cells (Holk and Lykkeboe 1995). An increase in oxygen affinity appeared for both carp and trout. Part of this increase could be explained by a lower content of organic phosphates, whereas the rest of the increase was ascribed to changes in the association constants of at least one of the phosphate-hemoglobin or oxygen-hemoglobin complexes. However, in spite of a marked swelling and a slightly lower content of organic phosphates, no change in the Φfa(i) appeared.