Abstract
Abstract
Normal and folate-deficient rats were partially hepatectomized and sacrificed at various times after the operation. The distribution of pteroylmono- and polyglutamates was evaluated by Sephadex G-15 chromatography and microbiological assay. The incorporation of thymidine into DNA was also studied. Deficient rats show a fall in penta-and hexaglutamates and intermediate forms beginning 12 hr after the operation. Monoglutamates diminished but less than the other compounds. In control rats the higher polyglutamates after an initial decrease rise to normal values at 180 hr; the intermediate forms had already increased at 12 hr and remained high at the following times and monoglutamates at first decreased but at 180 hr exceeded normal values. The rate of DNA synthesis is not only decreased, but also delayed in regenerating liver of deficient rats as compared with controls. The livers of deficient rats appear unable to synthesize adequate quantities of polyglutamates. This fact may explain the slowing down of the regenerative process in folic acid-deficient rats, demonstrated by lower and delayed thymidine incorporation into DNA.
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