Folate metabolism in the rat liver during regeneration after partial hepatectomy

1. Folate metabolism was studied during the early phases of liver regeneration after partial hepatectomy in rats accustomed to eating during the first 8h of a daily 12h dark period. 2. The content of 5-CH₃–H₄folate was drastically decreased during the first hours of regeneration. 3. The total HCO–H₄folate coenzymes showed a constant decrease during the first 3 days of regeneration, and a continuous interconversion between 5-HCO–H₄folate and 10-HCO–H₄folate. 4. 10-HCO–H₄folate synthetase, serine hydroxymethyl-transferase and 5,10-CH₂–H₄folate dehydrogenase activities were relatively low during the first hours after the operation, and increased only several hours later. 5. The increase in enzyme activities showed a stepwise pattern, apparently due to an interaction between the regeneration process and the controlled feeding schedules.