The metabolism of [3',5',9(n)-3H] pteroylglutamic acid by chicken liver in vivo. Effects of folate deficiency and vitamin B12 supplementation.

1. Control, folate-deficient and vitamin B12-supplemented chickens were given [3', 5', 9 (n)-3H] pteroylglutamic acid by intraperitoneal injection. After various time intervals (1.5 h-8d) the incorporation of radioactivity into hepatic folate derivatives was measured. 2. The results confirm that avian species have a faster assimilation of folate than most mammalian species. 3. Folate deficiency increased the incorporation and retention of [3H] pteroylglutamic acid. The degree of folate conjugation was unaffected by folate deficiency but the formyl to methyl folate ratio was decreased. 4. Vitamin B12 supplementation had no effect on the uptake or conjugation of [3H] pteroylglutamic acid, but increased the formyl to methyl folate ratio.