Abstract
1. Examination of the pantothenic acid (PaA) activity of homopantothenic acid (HOPA) derivatives revealed only a slight acceleration of growth of L. arabinosus 17-5 by α-hydroxyhomopantothenic acid (α-OH-HOPA) in a concentration higher than 10μg/tube. 2. HOPA, α- and β-OH-HOPA showed a competitive antagonistic action against PaA in both L. arabinosus 17-5 and Leuc. mesenteroides P-60. With 50% inhibition of growth as an index, the relative antagonistic action of HOPA, α- and β-OH-HOPA was 150, 300 and 500, respectively, in L. arabinosus and 350, ca. 5, 000 and ca. 4, 000, in Leuc. mesenteroides. 3. In experiments in chicks given 1mg/kg/day of PaA, the oral administration of 2.5-3g/day of HOPA resulted in the appearance of PaA deficiency symptoms and a decrease in liver CoA became apparent after administration of 2.0-2.5g. 4. All of the biological phenomena induced by HOPA derivatives such as growth inhibition of bacteria and pathological symptoms and decline of liver CoA in the chick are restored to normal by increasing the dose of PaA.
