THE RELATION OF PROTEIN INTAKE TO LEAD POISONING IN RATS

¹ From the Division of Industrial Hygiene, National Institute of Health, United States Public Health Service, Federal Security Agency, Bethesda, Maryland

1. Growth rates of white rats have been determined on synthetic diets containing 6, 13, and 20 per cent casein and on 6 per cent casein supplemented with 1 cystine and with dl methionine. The effect of adding 1.5 per cent lead chloride to these diets has been determined. Both ad libitum and paired feeding methods have been used.

2. Various levels of lead chloride and the effect of phosphate additions were studied in connection with 13 per cent casein diet.

3. Oxygen uptake of liver slices, hemoglobin, red cells, stippled cells, and polychromatocytes were also studied.

4. The toxicity of lead chloride as indicated by mortality, growth rate, and hemoglobin level is affected by the quantity and quality of the protein content of the diet.

5. Oxygen uptake of liver slices is not greatly affected by lead chloride feeding nor by variation in the protein content of the diet.

6. Several interpretations of the effect of lead chloride on growth are possible from this data. Lead chloride reduces growth rate (a) by reducing food intake, (b) by removing phosphate from the diet, (c) by diverting amino acids from use for growth to use for rebuilding hemoglobin.