K⁺ efflux properties of red cells from mice expressing exclusively human hemoglobins. We determined the total K⁺ efflux in red cells as described in “Materials and methods” in 330 mOsm isotonic (I) or 250 mOsm hypotonic (H) media when the anion was either NO₃^- (NO3), Cl^- (Cl), or sulfamate (SFM) at pH 7.4 or pH 7.0 in the presence or absence of 10 μM DIOA. (A) K⁺ efflux properties of red cells from a HbAKO mouse. This panel shows a representative experiment in red cells combined from 3 mice. Two different experiments were done on a total of 6 different mice. (B) K⁺ efflux properties of red cells from a NY1KO-γH mouse. This panel shows a representative experiment in red cells combined from 3 mice. Two different experiments were done on a total of 5 different mice. (C) K⁺ efflux properties of red cells from a HbCKO mouse. This panel shows a representative experiment in red cells combined from 3 mice. Three different experiments were done on a total of 6 different mice.