Changes in the haemoglobin types of sheep as a response to anaemia

Abstract

The response of sheep heterozygous for the hemoglobin variants Hb-A and Hb-B and sheep homozygous for Hb-B to the stress of severe experimental anemia has been reinvestigated. In animals subjected to extreme blood loss the Hb-A was replaced entirely by a new hemoglobin variant (Hb-C), whereas the production of Hb-B apparently was not affected. Under conditions of moderate blood loss, the replacement of Hb-A by Hb-C was partial. Hb-C was detectable in fairly constant concentrations in the blood of heterozygous sheep during the recovery phase of anemia. Hb-C differs from Hb-A and from Hb-B in electropheretic mobility and in its behavior in DEAE-cellulose chromatography. Hemoglobins A, B, C and foetal hemoglobin seem to share the same [alpha]-polypeptide chain, but the non-[alpha]-chains of each of the 4 hemoglobin types are distinctly different. The affinity of Hb-C for molecular oxygen was identical with that of Hb-A, and, therefore, different from that of Hb-B. No changes in oxygen affinities of total erythrocyte hemolysates of a heterozygous AB sheep and a homozygous B sheep were observed during the experimental anemia.