Abstract
1. The in vitro biosynthesis from 4′-phosphopantetheine to CoA was investigated and if was applied for determination of hepatic CoA precursors, such as 4′-phosphopantetheine and dephospho CoA, in albino rats. By this method, changes in CoA and its precursors in the liver with the days after birth were determined. In the liver a fairly large amount of precursors were found to exist as bound PaA along with CoA. This finding does not agree with the report of Novelli who found the majority of bound form of PaA to be CoA. These CoA and precursors were gradually increased as the days after birth elapsed until 30 days but their proportions were not particularly changed with the number of days.
2. Hepatic CoA value was lowered by administration of pantothenic acid deficient diet and the values of CoA precursors were further markedly reduced to replace the majority of bound form of pantothenic acid with CoA.
3. When various amounts of pantothenic acid and pantethine were added to a pantothenic acid deficient diet, the maximum hepatic CoA value was found in the group fed on the diet added with 9.2 μmoles per 100g of the diet. Further administration resulted in a tendency of mild decrease.
4. The group added with 2.3 to 23 μmoles showed an increase of CoA precursors, similarly to the CoA level. Addition of as large as 230 μmoles resulted in a decrease of precursors but the other bound form of pantothenic acid was reserved in a large amount.
5. Comparing the pantothenic acid added group and pantethine added group, the amount of hepatic CoA did not show any difference between the two groups. However, the proportion occupied by CoA in the total pantothenic acid amount was always high in the pantethine added group.
