Use of embryonic chick lens for screening potentially toxic chemicals

A system is described to monitor the metabolic activity of lenses isolated from chick embryos and incubated in suitable culture medium, with the purpose of screening potentially toxic compounds. Lenses which have not been exposed to such chemicals continue to produce acid for at least 2 weeks under these conditions. On the other hand, exposure of lenses for 4 hr to various aromatic compounds in concentrations of 0·5 m m or more causes partial or complete inhibition of acid production on subsequent incubation in the culture medium. In view of the biochemical parallels between the lens and the erythrocyte, the effects of aromatic haemolysins were studied in this system: phenylhydrazine and some other benzene derivatives which destroy erythrocytes were ineffective, whereas naphthoquinones and the antimalarial drug, primaquine, inhibited acid production by the lens. From the various observations, the change in pH of the medium appears to provide a simple but semi-quantitative method of screening compounds for toxicity to the embryonic chick lens, which may have application to the investigation of chemical cataractogenesis during developmental life.