Dissociation between maternal and fetal toxicity of methyl isocyanate in mice and rats. 1990

D R Varma, and I Guest, and S Smith, and S Mulay
Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada.

The contribution of maternal hormonal changes and pulmonary damage on the fetal toxicity of methyl isocyanate (MIC) was studied in mice and rats. Exposure to MIC decreased maternal plasma progesterone levels in mice that lost but not in mice that retained pregnancy. Fetal toxicity of MIC was not related to changes in maternal plasma corticosterone levels. Neither chronic administration of progesterone nor the suppression of pulmonary edema with dexamethasone decreased fetal toxicity of MIC. Embryos exposed in utero or in vitro to MIC vapor exhibited a concentration-dependent decrease in growth in culture. An acute dose (3 mmol/kg) of the MIC metabolites (methylamine, dimethylamine, trimethylamine, dimethyl urea) did not exert fetal toxicity. These data suggest that the fetal toxicity of MIC is partly independent of maternal toxicity and may result from its transfer across the placenta and interaction with fetal tissues.

UI MeSH Term Description Entries
D008431 Maternal-Fetal Exchange Exchange of substances between the maternal blood and the fetal blood at the PLACENTA via PLACENTAL CIRCULATION. The placental barrier excludes microbial or viral transmission. Transplacental Exposure,Exchange, Maternal-Fetal,Exposure, Transplacental,Maternal Fetal Exchange
D008815 Mice, Inbred Strains Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations, or by parent x offspring matings carried out with certain restrictions. All animals within an inbred strain trace back to a common ancestor in the twentieth generation. Inbred Mouse Strains,Inbred Strain of Mice,Inbred Strain of Mouse,Inbred Strains of Mice,Mouse, Inbred Strain,Inbred Mouse Strain,Mouse Inbred Strain,Mouse Inbred Strains,Mouse Strain, Inbred,Mouse Strains, Inbred,Strain, Inbred Mouse,Strains, Inbred Mouse
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
D011374 Progesterone The major progestational steroid that is secreted primarily by the CORPUS LUTEUM and the PLACENTA. Progesterone acts on the UTERUS, the MAMMARY GLANDS and the BRAIN. It is required in EMBRYO IMPLANTATION; PREGNANCY maintenance, and the development of mammary tissue for MILK production. Progesterone, converted from PREGNENOLONE, also serves as an intermediate in the biosynthesis of GONADAL STEROID HORMONES and adrenal CORTICOSTEROIDS. Pregnenedione,Progesterone, (13 alpha,17 alpha)-(+-)-Isomer,Progesterone, (17 alpha)-Isomer,Progesterone, (9 beta,10 alpha)-Isomer
D011919 Rats, Inbred Strains Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding. August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D003485 Cyanates Organic salts of cyanic acid containing the -OCN radical. Cyanate
D003907 Dexamethasone An anti-inflammatory 9-fluoro-glucocorticoid. Hexadecadrol,Decaject,Decaject-L.A.,Decameth,Decaspray,Dexasone,Dexpak,Hexadrol,Maxidex,Methylfluorprednisolone,Millicorten,Oradexon,Decaject L.A.
D005260 Female Females
D005314 Embryonic and Fetal Development Morphological and physiological development of EMBRYOS or FETUSES. Embryo and Fetal Development,Prenatal Programming,Programming, Prenatal
D005333 Fetus The unborn young of a viviparous mammal, in the postembryonic period, after the major structures have been outlined. In humans, the unborn young from the end of the eighth week after CONCEPTION until BIRTH, as distinguished from the earlier EMBRYO, MAMMALIAN. Fetal Structures,Fetal Tissue,Fetuses,Mummified Fetus,Retained Fetus,Fetal Structure,Fetal Tissues,Fetus, Mummified,Fetus, Retained,Structure, Fetal,Structures, Fetal,Tissue, Fetal,Tissues, Fetal

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