Experimental isovalthinuria, VI. Induction by cho­lesterol precursors and some other compounds

1. For the elucidation of the mechanism of isovalthinuria induction, some precursors of cholesterol biosynthesis and some other compounds were tested in guinea pigs to know whether they induced isovalthinuria or not. 2. Among the cholesterol precursors tested, isovaleric, β-methylcrotonic, and β-methylglutaconic acids were found to be strong inducers of isovalthinuria, but acetic acid, acetoacetic acid, β-hydroxy-β-methylglutaric acid, squalene, α-ketoisocaproic acid, and leucine were not. 3. Among the other compounds tested, palmitic acid and L-cysteine were found to be weak inducers of isovalthinuria. 4. Some antagonistic phenomena were found to occur. The inducing effect of isovaleric acid was inhibited strongly by dexamethasone or dehydrocholic acid, and weakly by insulin. The inducing effect of dexamethasone was inhibited by dehydrocholic acid or thyroxine. The inducing effect of dehydrocholic acid was inhibited by insulin or dexamethasone. 5. Although ethionine was not an inducer in itself, it acted as a substitute for methionine or cysteine in the case of the sulfur deficiency produced by prolonged feeding on bile acid. 6. Isovalthinuria was observed by the administration of bromural, but this effect may be a detoxication but not induction,