Abstract
A study of the storage of riboflavin, pantothenic acid, nicotinic acid, folic acid, and biotin in the liver was made in rats receiving various types of rations. A highly purified diet, adequate in those members of the vitamin B complex required for the production of excellent growth in rats, caused a marked reduction in the hepatic stores of folic acid and biotin compared with the amounts of these factors found in the liver of animals maintained in stock rations. The hepatic storage of these factors was further reduced by the incorporation of succinylsulfathiazole in such synthetic rations. The storage of riboflavin and nicotinic acid was not demonstrably influenced, a finding which indicates that no gross change in the liver occurred during sulfonamide administration. Despite the presence in the diet of a previously adequate amount of pantothenic acid, the inclusion of succinylsulfathiazole caused a reduction in the pantothenic acid content of the liver to a level as low as that produced by a diet devoid of pantothenic acid. Increasing the dietary intake of pantothenic acid or giving the vitamin parenterally did not cause a renewal of growth, failed to modify the signs of pantothenic acid deficiency, and left unaffected the severely reduced amount of pantothenic acid in the liver. Administration of crystalline biotin and a concentrate of folic acid caused a prompt restoration of growth, recovery from the signs of pantothenic acid deficiency, and a restoration of the pantothenic acid content of the liver to normal. It is suggested that folic acid (or a constitutent of the folic acid concentrate employed) and biotin are essential for the maintenance of growth and of the general health of rats given purified rations containing succinylsulfathiazole. At least a portion of the effect of these factors is attributed to their playing an essential role in the utilization of pantothenic acid.