Protein metabolism in the choline-deficient rat. I. Effect of choline on serum proteins.

Unless the choline content is sufficient to supply all of the required methyl groups, the amount of choline in a diet apparently determines the quantity of methionine used for protein synthesis and the quantity reserved for use as a methyl donor. This concept is supported by Treadwell’s demonstration (1) of the growth-stimulating effect of choline and Salmon’s observation (2) that the nutritive value of protein can be improved by incorporating choline into a deficient diet. In the present study, electrophoretic patterns of sera from rats fed a choline-deficient diet were compared with those from rats fed choline supplements in addition to the basal diet. The data showed that an 18 per cent casein diet did not provide all of the factors essential for the maintenance of normal serum albumin concentration and that the kidney damage of severely deficient animals caused the concentrations of the a-globulins and one of the P-globulins of the sera to increase.