Induction of haemolytic anaemia by substituted phenylhydrazines.

The induction of anaemia and reticulocytosis by arylhydrazines was influenced by substituents on the benzene ring of phenylhydrazine. Arylhydrazines with ortho substituents, which would hinder the binding by haemoglobin of a ligand derived from the arylhydrazine, resulted in the least anaemia and reticulocytosis. These results are consistent with a previous finding that hydrazinobenzoic acid, which did not produce a ferrihaemochrome from ferrihaemoglobin, did not induce anaemia. The parallelism between the formation of a ferrihaemoglobin compound and the induction of anaemia supports the hypothesis that destabilization of haemoglobin by the binding of a ligand derived from the aryl portion of an arylhydrazine is an essential step in arylhydrazine-induced haemolytic anaemia.