Methotrexate increases valproic acid-induced developmental toxicity, in particular neural tube defects in mice. 1992

M M Elmazar, and H Nau
Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Egypt.

The hypothesis that valproic acid-induced dysmorphogenesis may be due to an interference of this drug with folate metabolic pathways was further investigated by a study of a possible interaction of valproic acid (VPA) and the established folate antagonist methotrexate (MTX). The dihydrofolate reductase inhibitor MTX (1.25 and 2.5 mg/kg, i.p.) was injected 15 min prior to VPA (300 and 400 mg/kg, s.c.) in day 8 pregnant NMRI mice. Fetuses were examined for exencephaly, resorption, and fetal weight retardation on day 18 of gestation. MTX produced no exencephaly or reduction in fetal weight, and the 2.5-mg/kg dose caused 56% resorption. Higher doses (5-20 mg/kg) produced embryolethality and fetal weight retardation, but no exencephaly. VPA (300 and 400 mg/kg) administration resulted in 3.4% and 12.6% exencephaly and 9% and 19% resorptions, respectively. Coadministration of MTX with VPA significantly increased VPA-induced resorption and exencephaly rates as well as fetal weight retardation. Exencephaly induced by VPA 400 mg/kg was increased to 29.5% and 24.1% (P < 0.01 and P < 0.05) when given with 1.25 and 2.5 mg/kg MTX, respectively. MTX (2.5 mg/kg i.p.) did not alter transplacental VPA (400 mg/kg, s.c.) pharmacokinetics. These results support the view that VPA-induced teratogenesis may be mediated by interaction with folate metabolism.

UI MeSH Term Description Entries
D008727 Methotrexate An antineoplastic antimetabolite with immunosuppressant properties. It is an inhibitor of TETRAHYDROFOLATE DEHYDROGENASE and prevents the formation of tetrahydrofolate, necessary for synthesis of thymidylate, an essential component of DNA. Amethopterin,Methotrexate Hydrate,Methotrexate Sodium,Methotrexate, (D)-Isomer,Methotrexate, (DL)-Isomer,Methotrexate, Dicesium Salt,Methotrexate, Disodium Salt,Methotrexate, Sodium Salt,Mexate,Dicesium Salt Methotrexate,Hydrate, Methotrexate,Sodium, Methotrexate
D009436 Neural Tube Defects Congenital malformations of the central nervous system and adjacent structures related to defective neural tube closure during the first trimester of pregnancy generally occurring between days 18-29 of gestation. Ectodermal and mesodermal malformations (mainly involving the skull and vertebrae) may occur as a result of defects of neural tube closure. (From Joynt, Clinical Neurology, 1992, Ch55, pp31-41) Craniorachischisis,Developmental Defects, Neural Tube,Diastematomyelia,Exencephaly,Neurenteric Cyst,Spinal Cord Myelodysplasia,Tethered Cord Syndrome,Acrania,Developmental Neural Tube Defects,Iniencephaly,Neural Tube Developmental Defects,Neuroenteric Cyst,Occult Spinal Dysraphism,Occult Spinal Dysraphism Sequence,Tethered Spinal Cord Syndrome,Acranias,Craniorachischises,Cyst, Neurenteric,Cyst, Neuroenteric,Cysts, Neurenteric,Cysts, Neuroenteric,Defect, Neural Tube,Defects, Neural Tube,Diastematomyelias,Dysraphism, Occult Spinal,Dysraphisms, Occult Spinal,Exencephalies,Iniencephalies,Myelodysplasia, Spinal Cord,Myelodysplasias, Spinal Cord,Neural Tube Defect,Neurenteric Cysts,Neuroenteric Cysts,Occult Spinal Dysraphisms,Spinal Cord Myelodysplasias,Spinal Dysraphism, Occult,Spinal Dysraphisms, Occult,Tethered Cord Syndromes
D011247 Pregnancy The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH. Gestation,Pregnancies
D004357 Drug Synergism The action of a drug in promoting or enhancing the effectiveness of another drug. Drug Potentiation,Drug Augmentation,Augmentation, Drug,Augmentations, Drug,Drug Augmentations,Drug Potentiations,Drug Synergisms,Potentiation, Drug,Potentiations, Drug,Synergism, Drug,Synergisms, Drug
D004677 Encephalocele Brain tissue herniation through a congenital or acquired defect in the skull. The majority of congenital encephaloceles occur in the occipital or frontal regions. Clinical features include a protuberant mass that may be pulsatile. The quantity and location of protruding neural tissue determines the type and degree of neurologic deficit. Visual defects, psychomotor developmental delay, and persistent motor deficits frequently occur. Frontal Encephalocele,Hernia, Cerebral,Occipital Encephalocele,Acquired Encephalocele,Bifid Cranium,Cephalocele,Cerebellar Hernia,Cerebellar Herniation,Cranial Meningoencephalocele,Craniocele,Cranium Bifidum,Encephalocele, Acquired,Encephalocele, Frontal,Encephalocele, Occipital,Encephalocele, Sincipital,Notoencephalocele,Sincipital Encephalocele,Tonsillar Hernia,Tonsillar Herniation,Acquired Encephaloceles,Bifid Craniums,Bifidum, Cranium,Bifidums, Cranium,Cephaloceles,Cerebellar Hernias,Cerebellar Herniations,Cerebral Hernia,Cerebral Hernias,Cranial Meningoencephaloceles,Cranioceles,Cranium Bifidums,Cranium, Bifid,Craniums, Bifid,Encephaloceles,Encephaloceles, Acquired,Encephaloceles, Frontal,Encephaloceles, Occipital,Encephaloceles, Sincipital,Frontal Encephaloceles,Hernia, Cerebellar,Hernia, Tonsillar,Hernias, Cerebellar,Hernias, Cerebral,Hernias, Tonsillar,Herniation, Cerebellar,Herniation, Tonsillar,Herniations, Cerebellar,Herniations, Tonsillar,Meningoencephalocele, Cranial,Meningoencephaloceles, Cranial,Notoencephaloceles,Occipital Encephaloceles,Sincipital Encephaloceles,Tonsillar Hernias,Tonsillar Herniations
D005260 Female Females
D005492 Folic Acid A member of the vitamin B family that stimulates the hematopoietic system. It is present in the liver and kidney and is found in mushrooms, spinach, yeast, green leaves, and grasses (POACEAE). Folic acid is used in the treatment and prevention of folate deficiencies and megaloblastic anemia. Pteroylglutamic Acid,Vitamin M,Folacin,Folate,Folic Acid, (D)-Isomer,Folic Acid, (DL)-Isomer,Folic Acid, Calcium Salt (1:1),Folic Acid, Monopotassium Salt,Folic Acid, Monosodium Salt,Folic Acid, Potassium Salt,Folic Acid, Sodium Salt,Folvite,Vitamin B9,B9, Vitamin
D000014 Abnormalities, Drug-Induced Congenital abnormalities caused by medicinal substances or drugs of abuse given to or taken by the mother, or to which she is inadvertently exposed during the manufacture of such substances. The concept excludes abnormalities resulting from exposure to non-medicinal chemicals in the environment. Drug-Induced Abnormalities,Abnormalities, Drug Induced,Abnormality, Drug-Induced,Drug Induced Abnormalities,Drug-Induced Abnormality
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D014635 Valproic Acid A fatty acid with anticonvulsant and anti-manic properties that is used in the treatment of EPILEPSY and BIPOLAR DISORDER. The mechanisms of its therapeutic actions are not well understood. It may act by increasing GAMMA-AMINOBUTYRIC ACID levels in the brain or by altering the properties of VOLTAGE-GATED SODIUM CHANNELS. Dipropyl Acetate,Divalproex,Sodium Valproate,2-Propylpentanoic Acid,Calcium Valproate,Convulsofin,Depakene,Depakine,Depakote,Divalproex Sodium,Ergenyl,Magnesium Valproate,Propylisopropylacetic Acid,Semisodium Valproate,Valproate,Valproate Calcium,Valproate Sodium,Valproic Acid, Sodium Salt (2:1),Vupral,2 Propylpentanoic Acid

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