Abstract
The amount of biologically active folate excreted in the urine corresponds to a small fraction of the recommended dietary allowance, suggesting that a large amount of folate is excreted as its catabolites. A strategy of assessing folate requirement by measuring the daily urinary levels of products of folate catabolism depends on the demonstration of an exclusive mechanism of breakdown as well as a suitable marker of the catabolic process. Rats were given [3H] and [14C]folic acid by gastric intubation daily for 10 d to simulate normal dietary intake of the vitamin. Total urine was collected throughout this period as well as for the following 10 d. Reverse-phase HPLC of the radiolabeled urinary products revealed the presence of a variety of intact folates as well as products of C9-N10 scission of the folate molecule, pteridines, para-aminobenzoylglutamate and para-acetamidobenzoylglutmate. We detected no other N10-containing catabolites, nor did we find the oxidized folate derivative ‘4α-hydroxy-5-methyltetrahydrofolate’. Of all the urinary folate metabolites, only para-acetamidobenzoylglutmate persisted at high levels up to 10 d after radiolabel treatment was withdrawn. We conclude that folate catabolism occurs exclusively through C9-N10 cleavage and that measurement of urinary para-acetamidobenzoylglutmate provides a suitable indicator of daily folate turnover.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
