Abstract
The in vivo conversion ratio of N1-methylnicotinamide (NMN) to N1-methyl-2-pyridone-5-carboxamide (2-PY) and N1-methyl-4-pyridone-3-carboxamide (4-PY) as a parameter for the estimation of aldehyde oxidase level in rats was examined. NMN and its pyridones (2-PY and 4-PY) are usually detected in the urine of rats. When we measured the ratio of the amount of pyridones to the total amount of NMN and pyridones (RP value) in the urine of rats, marked intraspecies variations were observed. The variation in RP value among strains was closely related to the differences of liver aldehyde oxidase activity measured with NMN as a substrate. RP values after administration of NMN to different strains of rats confirmed the existence of strain differences of aldehyde oxidase activity in vivo. We demonstrated that measurements of NMN and its pyridones usually excreted in the urine can be used to predict the in vivo level of aldehyde oxidase.
Footnotes
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This work was supported by a Grant-in-Aid for Scientific Research on Priority Areas from the Japanese Ministry of Education, Science, Sports and Culture, and a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science.
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Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
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doi:10.1124/dmd.105.006544.
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ABBREVIATIONS: NMN, N1-methylnicotinamide; 2-PY, N1-methyl-2-pyridone-5-carboxamide; 4-PY, N1-methyl-4-pyridone-3-carboxamide; HPLC, high-performance liquid chromatography; RP value, the ratio of the amounts of pyridones to the total amounts of NMN and pyridones.
- Received July 15, 2005.
- Accepted November 17, 2005.
- The American Society for Pharmacology and Experimental Therapeutics
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