Hereditary hypochromic microcytic anemia in the laboratory rat.

The group of 17 irradiated rats including the animal that produced anemic progeny (X2) belonged to a stock of rats randomly bred in our laboratory since 1930. The X2 female was one of five females in a litter, which were X-irradiated under conditions reported earlier (SLADICSIMIC et al. 1963). All irradiated females were mated with normal males from the stock and brother-sister matings for each line were carried through four to eight filial generations. Rats which had giyen anemic young in their offspring, were crossed with each other and with unrelated and related anemic animals. Anemic rats of both sexes were crossed with each other and with unrelated and related normal animals. The concentration of hemoglobin was measured by the method of KHALIFA and SALAH (1951). The osmotic resistance of erythrocytes was determined by Simmel’s method. Hemolysis was considered complete at 90 to 100% and absent at 0 to 10% lytic levels. All peripheral blood samples were obtained from the tail. The Price Jones curves for the diameters of erythrocytes were obtained from fixed smears of peripheral blood with the use of an ocular micrometer, and the hematocrit values with the Drummond Microhematocrit. Peripheral blood cells were counted in the standard chambers. Blood smears were stained with the Giemsa technique. Since it was found in the course of our experiments that anemic rats 30 days of age and older responded to intramuscularly injected iron with an increase in survival time, anemic rats were treated with an iron dextran complex (Myofer, Farbwerke Hoechst AG). The dose was 0.5mg per day, except that pregnant anemic rats received l.Omg per day.