title: Folate deficiency and in vitro palatogenesis I: effects of a folate-deficient culture on rabbit palate fusion and folate pools.
abstract: Folate compounds are essential for nucleic acid metabolism and data from in vitro experiments have shown that folatee deficiency during pregnancy induced by dietary deprivation or folate antagonists is teratogenic. The craniofacial complex is a main target of this teratogen, with the lip and palate being especially vulnerable. The direct effect of folate deficiency on a target teratogenic tissue was, therefore, examined in vitro using fetal rabbit palates in an organ culture system. Folate pool sizes in the palates on the 4 days preceding fusion were determined by competitive binding assay. There was a sharp decrease in folate levels from 2.63 +/- 0.86 ng/mg wet wt on Day 15 of gestation to 1.23 +/- 0.35 ng/mg on Day 16 and 0.59 +/- 0.12 ng/mg on Day 17. The folat pool size on Day 14 was found to be quite variable with a mean of 1.93 ng/mg wet wt. Comparable results were obtained when the folate pool sizes were expressed as nanograms of folate per milligram of protein. The effect of a folate-deficiency culture medium on in vitro fusion and folate pool sizes was examined. The results of incubating palatal shelves excised on Days 14, 15, 16, and 17 of gestation for 5, 4, 3, and 2 days, respectively, show that a folate-depleted medium neither prevented nor delayed fusion. An examination of the palatal pool size after incubation in folate-deficient media revealed that while there was some decrease in folate levels, the palates apparently retained sufficient folate to support cellular activity.
mesh_terms: D000014:Abnormalities, Drug-Induced / Q000209:etiology; D000818:Animals; D004247:DNA / Q000096:biosynthesis; D005260:Female; D005492:Folic Acid / Q000378:metabolism; D005494:Folic Acid Deficiency / Q000150:complications / Q000196:embryology*; D066298:In Vitro Techniques; D008727:Methotrexate / Q000633:toxicity; D010159:Palate / Q000196:embryology*; D011247:Pregnancy; D011817:Rabbits
chemical_list: D004247:DNA; D005492:Folic Acid; D008727:Methotrexate