Regulation of hepatic betaine-homocysteine methyltransferase by dietary betaine.
The level of betaine-homocysteine methyltransferase increases in the livers of rats fed diets supplemented with betaine or choline. The increase occurs within 3 days following the change in diet. When we administered betaine by intraperitoneal injection to rats fed choline-free diets, we observed a similar increase within 24 hours. Since betaine-homocysteine methyltransferase catalyzes a reaction which is essential for the catabolism of betaine, these changes provide a means for adaptation to excessive levels of dietary choline and betaine.
D000818:Animals; D001622:Betaine / Q000008:administration & dosage / Q000032:analysis / Q000378:metabolism*; D002794:Choline / Q000008:administration & dosage / Q000032:analysis / Q000378:metabolism; D005527:Food, Fortified; D050904:Homocysteine S-Methyltransferase; D007274:Injections, Intraperitoneal; D008099:Liver / Q000032:analysis / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D008780:Methyltransferases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D001622:Betaine; D008780:Methyltransferases; D050904:Homocysteine S-Methyltransferase; D002794:Choline