Effect of Vitamin B12 in Choline Deficiency in the Rat

Abstract

Several diets varying in methionine content and low in choline and vitamin B12 were prepared using different amounts of extracted peanut meal supplemented with amino acids. Most of the diets contained added homocystine as well. Marked growth inhibition was observed within 2 to 3 weeks in weanling male rats and, provided the level of methionine in the diet was not too low, vitamin B12, choline or methionine supplementation promoted rapid and approximately equal growth. The 3 supplements also prevented fatty liver, liver fibrosis, and kidney scarring although vitamin B12 was not always completely effective. Urinary formiminoglutamic acid (FIGLU) excretion was high with the deficient diet and was decreased to nearly zero by vitamin B12 or methionine supplements. The presence or absence of folic acid in these diets had little effect on the performance of the animals or the lesions seen although a moderate growth response occurred in the presence of vitamin B12. When homocystine was not included in the diet (and methionine synthesis presumably blocked), supplements of vitamin B12 and folic acid did not completely prevent FIGLU excretion. The excretion of this metabolite would not appear to be due to a deficiency of vitamin B12 or folic acid per se.