Lethal Amounts of Casein, Casein Salts and Hydrolyzed Casein Given Orally to Albino Rats

Abstract

The lethal dose of casein given as an aqueous suspension intragastrically to albino rats was estimated to be well over 1000 g/kg administered over a period of 2 weeks but could not be definitely established because deaths were due in part to distilled water in the suspension. The LD₅₀ of the water-soluble sodium and calcium salts of casein was estimated to be some 400–500 g/kg given over a 5-day period, the intoxication being due mainly to salt effects. The LD₅₀ ± SE of pancreatin-hydrolyzed casein was found to be 26.0 ± 1.6 g/kg, death occurred at 2 to 4 hours and was due to a violent gastroenteritis, blood and tissue dehydration, widespread capillary-venous congestion, coma and respiratory failure. Survivors of the latter group recovered clinically in 2 to 3 days but some changes in organ weights were significantly abnormal at 2 weeks and even at 1 month. The results indicate it is almost impossible to administer lethal amounts of casein orally to albino rats but that toxic effects can be produced by water-soluble salts of casein and particularly by the amino acids and polypeptides of hydrolyzed casein.