ascorbic-acid and trimethylamine

ascorbic-acid has been researched along with trimethylamine* in 3 studies

Other Studies

3 other study(ies) available for ascorbic-acid and trimethylamine

ArticleYear
Flavin-containing monooxygenase activity can be inhibited by nitric oxide-mediated S-nitrosylation.
    Life sciences, 2004, Oct-08, Volume: 75, Issue:21

    Nitric oxide (NO) modifies the functions of a variety of proteins containing cysteine thiols or transition-metal centers, particularly by S-nitrosylation. In inflamed liver, NO is overproduced and hepatic drug-metabolizing enzymes, the flavin-containing monooxygenases (FMOs) and cytochrome P450s (CYPs), are suppressed. However, the NO-related mechanisms underlying the loss of these activities are not well understood, particularly for FMOs. In this study, we suggest that FMO3, the major FMO in human liver, is modified post-translationally by NO. This hypothesis is based on the imbalance observed between the decrease in FMO3 expression (40.7% of controls) and FMO3-specific ranitidine N-oxidation activity (15.1%), and on the partial or complete reversibility of FMO inhibition by sulfhydryl-reducing regents such as DTT (effective on both S-S and S-NO adducts) and ascorbate (effective on S-NO only). Furthermore, NO donors (SNP, SNAP, and Sin-1), including the pure NO donor DEA/NO, directly suppressed in vitro FMO activity (N- or S-oxidation of ranitidine, trimethylamine, and thiobenzamide) in human liver microsomal proteins and recombinant human FMO3. These activities were restored completely after treatment with DTT or ascorbate. These results suggest that NO-mediated S-nitrosylation is involved in the rigorous inhibition of FMO activity in vitro and in vivo, resulting in the suppression of FMO-based drug metabolism or detoxification.

    Topics: Adult; Ascorbic Acid; Carcinoma, Hepatocellular; Dithiothreitol; Enzyme Inhibitors; Hepatitis B, Chronic; Humans; Liver; Liver Cirrhosis; Liver Neoplasms; Methylamines; Microsomes, Liver; Middle Aged; Nitric Oxide; Nitric Oxide Donors; Nitrosation; Oxygenases; Ranitidine; Recombinant Proteins; Thioamides

2004
Teratogenic and macromolecular synthesis inhibitory effects of trimethylamine on mouse embryos in culture.
    Journal of toxicology and environmental health, 1992, Volume: 36, Issue:1

    Trimethylamine (TMA) is an aliphatic amine, and its blood levels can increase after ingestion of certain foods, such as fish, and during disease states, such as chronic renal failure. We recently reported that TMA can inhibit fetal development in vivo and in vitro in mice. The present studies were done to find out if the inhibitory effects of TMA on embryonic development are caused by a decrease in macromolecular synthesis, using mouse embryo cultures as the experimental model. At a submaximally toxic concentration (0.75mM), TMA inhibited the growth of embryos to approximately 70% of control and caused neural-tube defects in 73% of embryos. By 42 h of culture, DNA, RNA, and protein content of TMA-treated embryos were approximately 50% of the control values. Embryotoxic effects of TMA were not caused by changes in pH and osmolarity of the culture media. The inhibitory effects of TMA on embryonic growth were time dependent and apparent at 2-4 h of culture. The inhibition of growth was accompanied by a decrease in the incorporation of tritium-labeled thymidine, uridine, and leucine into DNA, RNA, and proteins, respectively. Thiols (L- and D-cysteine, glutathione) and the antioxidant L-ascorbic acid did not cause significant antagonism of embryotoxic effects of TMA. It is concluded that TMA exerts teratogenic effects on mouse embryos in culture and inhibits their growth by reducing macromolecular synthesis; these effects may not involve glutathione depletion or generation of free radicals.

    Topics: Abnormalities, Drug-Induced; Animals; Ascorbic Acid; Culture Techniques; DNA; Embryo, Mammalian; Embryonic and Fetal Development; Female; Fetal Growth Retardation; Hydrogen-Ion Concentration; Leucine; Macromolecular Substances; Methylamines; Mice; Models, Biological; Osmolar Concentration; Pregnancy; Protein Biosynthesis; RNA; Sulfhydryl Compounds; Thymidine; Tritium; Uridine

1992
Potentiation of ferrous sulphate and ascorbate on the microbial transformation of endogenous trimethylamine N-oxide to trimethylamine and dimethylamine in squid extracts.
    Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, 1989, Volume: 27, Issue:9

    The levels of trimethylamine N-oxide (TMAO) in the New Zealand (Nototodarus sloani) species of squid extracts were extremely high (above 9200 ppm). When the extracts were incubated for 2 days at 25 degrees C, approximately 60% TMAO was converted to trimethylamine (TMA) and dimethylamine (DMA). This conversion was very low or negligible at 4 degrees C, but was potentiated by the presence of ferrous sulphate (0.014 M) and ascorbate (0.014 M). Citrobacter freundii and Aeromonas hydrophilia were isolated from the extracts. Cultures of these two micro-organisms and of Escherichia coli were active in catalysing the conversion of TMAO to TMA and DMA either in extract or in aqueous solution. Chloramphenicol (0.416 mg/ml) completely inhibited the growth of these micro-organisms and also effectively blocked the conversion of endogenous TMAO to TMA in the extracts. The present findings suggest that gastro-intestinal flora and dietary ferrous salts and ascorbate may play important roles in the conversion of TMAO to TMA and DMA in man following the ingestion of squid and other TMAO-containing seafoods.

    Topics: Animals; Ascorbic Acid; Bacteria; Chloramphenicol; Decapodiformes; Dimethylamines; Drug Synergism; Ferrous Compounds; Methylamines

1989
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