The metabolism of 5-methyltetrahydropteroyl-L-glutamic acid and its oxidation products in the rat.
Folate metabolism in the rat was investigated using radiolabelled 5-methyltetrahydropteroylglutamate (5-CH3-H4PteGlu) and its oxidation products. 5-CH3-H4PteGlu is absorbed completely from the intestine, although in some preparations it is an equimolecular mixture of C-6 epimers, only one of which is naturally present in biological systems. The methyl group is incorporated into non-folate compounds, including methionine and creatine. No evidence was observed for the oxidation of the methyl group of 5-CH3-H4PteGlu to form other folate types. The tetrahydrofolate moiety of 5-CH3-H4PteGlu is metabolized in a similar manner to folic acid, forming formyl folates and tissue polyglutamates, and is catabolized by scission. The triazine oxidation product of 5-CH3-H4PteGlu is not metabolized by the rat or its gut microflora. 5-Methyl-5,6-dihydropteroylglutamate, however, is assimilated into the folate pool, but is substantially broken down by passage through the gut. The possible implication of this in scorbutic diets is discussed.
D000818:Animals; D005492:Folic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D008297:Male; D010084:Oxidation-Reduction; D051381:Rats; D011919:Rats, Inbred Strains; D013763:Tetrahydrofolates / Q000378:metabolism* / Q000652:urine; D014018:Tissue Distribution; D014227:Triazines
D013763:Tetrahydrofolates; D014227:Triazines; C036215:5-methyl-5,6-dihydropteroylglutamic acid; D005492:Folic Acid; C005984:5-methyltetrahydrofolate