Impairment of erythropoiesis in rats exposed to environmental pollutants.

The extent to which halogen compounds interfere with erythropoiesis is still unclear. This paper reports an evaluation of the effect of repeated exposure to carbon tetrachloride (CCl4) in air on red blood cell (RBC) creatine concentration. Creatine is neither synthetised nor metabolised in circulating RBC and decreases over the lifespan of red cells. It can thus be taken as a reliable indicator of mean RBC age, and hence of cell viability and bone marrow efficiency. Following inducement of hemolysis with phenylhydrazine (PHH) to stimulate erythropoiesis, creatine levels rose in the controls. This increase was significantly less in the CCl4-treated animals. It is not yet certain whether this inhibition reflects impaired marrow efficiency, enhanced RBC destruction in the marrow, or block of the release of mature RBC. The fact that such inhibition takes place, however, is of importance as a predictive factor in environmental toxicology, since it appears before changes in other blood parameters or signs of liver toxicity are observed.