Choline Metabolism

Abstract

Hemorrhagic degeneration in young rats is absent or slight if a low choline diet contains more than 0.8% of methionine, regardless of whether this level is attained by supplementary methionine or by protein levels high in casein, lactalbumin or fibrin. These results support the conclusion that methionine supplies methyl groups for the synthesis of choline. Choline is a dietary essential if the ration contains less than 0.8% of methionine. The choline requirement varies inversely with the dietary methionine and is increased by dietary cystine. The effect of cystine is observed only on diets low in cystine and low in either choline or methionine and is not proportional to the level of supplementary cystine. A possible explanation of the effect of cystine is proposed. An exceptional increase in kidney weight results on diets containing 18% of casein and 22% of gelatin even though hemorrhagic degeneration is prevented by methionine or by choline.