Choline Biosynthesis in Germfree Rats

Liver choline biosynthesis was studied in germfree rats receiving a choline-deficient diet. Weanling conventional open-animal-room and ex-gennfree con ventionalized rats fed the choline-deficient diet for 2 weeks had elevated liver fat and decreased specific activities of liver choline following injection of 2 ,tiCi14CH3-labeled methionine into the portal vein. On the other hand, in germfree rats fed the choline- deficient diet there was no significant increase in liver fat nor was there a decrease in the rate of liver choline biosynthesis as measured by labeled methyl transfer. In these respects germfree rats fed a choline-deficient diet appeared to be the same as control rats fed a diet with adequate choline. These findings are consistent with a previous observation of a lessened nephropathy in germfree rats fed a choline-deficient diet, and also are similar to results obtained with conventional rats in which coprophagy had been prevented.