ninopterin and Folic-Acid-Deficiency

Crude X-methyl folate and two purified fractions (purified X-methyl folate and 9-methyl folate) were evaluated as possible folic acid antagonists. Antifolate activity was measured by the deoxyuridine suppression assay, direct measurement of dihydrofolate reductase and morphological changes characteristic of folate deficiency. Cytotoxicity was evaluated by cell growth curves. These drugs were studied in freshly obtained human normal evaluated by cell growth curves. These drugs were studied in freshly obtained human normal bone marrow and leukemia cells as well as in three established cell lines HL-60 (human promyelocytic leukemia), CEM (human T lymphocytes), and L1210 (murine lymphoid leukemia). Purified X-methyl folate and 9-methyl folate at concentrations up to 2X10(-5) M failed to induce cell toxicity or inhibit deoxyuridine suppression of 3H-thymidine into DNA. Dihydrofolate reductase was not inhibited by 9-methyl folate but was partially inhibited by purified X-methyl folate. Crude X-methyl folate (2X10(-1) M) is a weak folate antagonist as compared to methotrexate since it requires a 1,000-fold higher concentration to inhibit cell growth and dihydrofolate reductase activity. In addition, the crude X-methyl folate contains a folate-like fraction since it will correct the abnormal deoxyuridine suppression in folate-depleted cells. None of the drugs tested were able to induce myeloid differentiation in the HL-60 cells. The data suggest that 9-methyl folate would not be active as a folate antagonist antitumor agent and that purified and crude X-methyl folate in large concentrations will inhibit folate metabolism. Additional studies are needed to remove the folate-like activity in the crude material in order to further establish the antitumor effects of the crude X-methyl folate.

Topics: Cell Differentiation; Cell Line; Deoxyuridine; Folic Acid; Folic Acid Antagonists; Folic Acid Deficiency; Humans

Pregnant rats were administered the teratogen and synthetic analogue of folic acid, 9-methyl pteroylglutamic acid, on the 11th day of gestation and placed on a semisynthetic diet containing the antagonist but lacking the vitamin until the 14th gestational day. This transitory maternal folic acid deficiency results in multiple congenital skeletal malformations. Control animals were administered a folic acid-supplemented regimen. Hexosamine levels were measured in fetal tissues, i.e. limbs, livers, and yolk sacs, in order to monitor the accumulation of a primary constituent of the extracellular matrix, i.e. glycosaminoglycans. Fetal tissues were obtained for hexosamine analysis on the 16th and 18th days of gestation. The teratogenic and transitory folic acid-deficient regimen resulted in (1) a significant reduction in the accumulation of hexosamine in fetal limbs by the 16th day of gestation, and (2) a significant increase in the accumulation of hexosamine in fetal livers by the 16th day of gestation. The regimen was observed to have had no effect on hexosamine accumulation by the yolk sac. Furthermore, no significant effect on hexosamine accumulation from the 16th to the 18th day of gestation was observed in any of the tissues studied.

Topics: Animals; Cartilage; Female; Folic Acid; Folic Acid Antagonists; Folic Acid Deficiency; Gestational Age; Hexosamines; Liver; Pregnancy; Pregnancy Complications; Rats