Hepatic free choline and betaine and the utilization of dietary protein in the choline-deficient rat.

In the rat, exclusion of choline from a carbohydrate-rich, 10% casein diet, resulted in a drastic reduction of betaine in the liver. The amount of unesterified choline was not lowered to the same extent. Both unesterified choline and total lipids in the liver were increased by rats fed a choline-deficient diet supplemented with 0.5% L-methionine compared to rats given an unsupplemented choline-deficient diet. The amount of betaine was low in both groups compared to choline-supplemented rats. Dietary choline deficiency lowered the biological value of casein only slightly. Statistically significant effects were seen only in some of the experiments when potato starch was used as the carbohydrate source but not when maize starch was used. The choline-deficient potato starch diet gave rise to a more severe liver fattening that the corresponding maize starch diet.