Study on in vivo and in vitro metabolism of dimethylformamide in male and female rats

doi:10.1016/0300-483X(84)90023-4

Toxicology

Volume 29, Issue 3, January 1984, Pages 221-234

https://doi.org/10.1016/0300-483X(84)90023-4 Get rights and content

Abstract

The study of dimethylformamide (DMF) metabolism by rat tissues in vitro indicates that formaldehyde is not a metabolic product as previously reported [1]. Furthermore, no other monocarbon derivative (CO, CH₃OH, HCOOH, CH₄) was detected when DMF was incubated with a fortified liver preparation. One metabolic product is methylhydroxymethylformamide (DMF- OH) measured as N-methylformamide (NMF) due to the breakdown of the hydroxymethyl group during gas chromatography. It was usually believed that the main metabolite excreted in urine following administration of DMF to male and female rats was N.M.F. The results of this study indicate that DMF-OH constitutes the main metabolite in vivo. A quantitatively less inmportant urinary metabolite, hydroxymethylformamide (NMFOH), is determined as formamide (F) by gase chromatography, In male and female rats, partial hepatectomy reduces markedly the in vivo biotransformation of DMF. Following administration of DMF or NMF, the total amount of metabolites (DMFOH and/or NMFOH) excerted in urine is identical in both sexes, but female rats excrete more unchanged parent compound than male rats. The rate of NMFOH excretion in urine following high doses of DMF supports the hypothesis that DMP may inhibit its own bioransformation.

References (15)

J.R. Barnes et al.
The metabolism of dimethylformamide and diemthylacetamide
Toxicol. Appl. Pharmacol.
(1972)
G. Triebig et al.
A simple and reliable enzymatic assay for the determination of formic acid in urine
Clin. Chim. Acta
(1980)
O.H. Lowry et al.
Protein measurement with the folin phenol reagent
J. Biol. Chem.
(1951)
G. Kimmerle et al.
Metabolism studies of N,N-dimethylformamide. I. Studies in rats and dogs
Int. Arch. Arbeitsmed.
(1975)
R. Lauwerys et al.
Biological surveillance of workers exposed to dimethylformamide and the influence of skin protection on its percutaneous absorption
Int. Arch. Occup. Environ. Health
(1980)
M.E. Maxfield et al.
Urinary excretion of metabolite following experimental human exposure to dimethylformamide and dimethylacetamide
J. Occup. Med.
(1975)
R. Lauwerys

There are more references available in the full text version of this article.

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Liver and heart toxicity due to 90-day oral exposure of ICR mice to N,N-dimethylformamide
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It is an excellent solvent and is widely used in many countries (WHO, 2001). DMF is metabolized by cytochrome P4502E1 to monomethyl and formamide derivatives such as N-hydroxymethyl-N-methylformamide (HMMF) (Scailteur et al., 1984). HMMF undergoes thermolytic degradation to form formaldehyde and N-methylformamide (NMF).
N,N-dimethylformamide (DMF) is a colorless liquid with a faint amine odor, which is widely used in the world. DMF exposure may induce adverse effects on liver, but few studies showed damage to heart after exposure to DMF. In the present study, DMF was administered to ICR mice with the doses of 0.32, 0.63 and 1.26 g/kg of body weight by gavage for 90 days. The increase in the relative liver weight is accompanied with the presence of the centrilobular hepatocellular hypertrophy as well as increased serum levels of aspartate transaminase (AST) and alanine transaminase (ALT). An increase of malondialdehyde (MDA) level was shown in liver homogenate, while superoxide dismutase (SOD) and glutathione (GSH) activities decreased. Heart damage was also shown in mice exposed to DMF for 90 days, although pathological examination showed only slight inflammatory cell infiltration. Increased levels of serum lactate dehydrogenase (LDH), isoenzymes of creatine kinase (CK-MB) and cardiac troponin I (cTnI) were shown. Increased level of MDA was also shown in heart homogenate, in contrast with the decreased activity of SOD. These data suggested that the administration of DMF could induce liver and heart injuries and oxidative stress was involved in the toxic effects.
The effects of simultaneous exposure to methyl ethyl ketone and toluene on urinary biomarkers of occupational N,N-dimethylformamide exposure
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General regulations and risk assessment regarding toxicants are single-compound oriented even though humans are exposed to multi-chemicals in the general environment. This study investigated the effects of different levels of N,N-dimethylformamide (DMF) and co-exposure levels of methyl ethyl ketone (MEK) and toluene (TOL) on two biomarkers of DMF exposure: non-metabolized urinary (U-)DMF and the DMF metabolite urinary N-methylformamide (NMF). Thirty-five workers were selected from a two-stage field investigation strategy and were classified into four groups based on DMF exposure and co-exposure levels. Breathing-zone air concentrations of DMF, MEK, and TOL as well as dermal DMF exposure were determined. Post-shift U-DMF and U-NMF levels were determined for each individual. U-DMF concentrations were significantly higher in high-DMF groups than in low-DMF groups, but U-NMF concentrations were significantly (P < 0.05) lower in the high-DMF-high-co-exposure group than in the high-DMF-low-co-exposure group; there were no significant differences between two low-DMF groups. The ratio of U-NMF to U-DMF showed the biotransformation from DMF to NMF was significantly suppressed at high co-exposure (P < 0.001) for high-DMF exposure groups, possibly because of competitive inhibition of CYP2E1, the responsible enzyme involved. Due to the ubiquity of MEK/TOL in DMF-exposed occupational settings, the biological exposure index for occupational DMF exposure should be re-evaluated at high co-exposure levels.
Mercapturic acids in the biological monitoring of occupational exposure to chemicals
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This paper reviews several procedures for determination of mercapturic acids in urine. Special attention was paid to methods useful in relation to human exposure to industrial pollutants, without any description for less sensitive methods used in animal research. Gas chromatographic and liquid chromatographic procedures were considered together with the little information available about thin layer chromatography and immunochemical techniques. After a description of the main industrial pollutants which lead to synthesis of their specific mercapturic acids, the methods for analysing these products are synthetically reported. The comparison among difficulties in sample preparation, complexity of instrumentation and their cost/benefit ratio are discussed.
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A new high-performance liquid chromatographic (HPLC) method is described for the determination of urinary N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC), the final product of the conjugation reaction between a metabolic intermediate of N,N-dimethylformamide (DMF) and glutathione. Urine samples were purified by C₁₈ solid-phase extraction and then directly analysed by HPLC with an Aminex Ion Exclusion HPX-87H column maintained at 25°C and a UV detector set at 196 nm. Under isocratic conditions (2.4 mM sulphuric acid, flow-rate=0.6 ml/min) AMCC eluted at 20.2 min. The reproducibility (C.V.%) was 1.3–2.7% (intra- and inter-assay, N=5); the accuracy was 98.0±1.7% at 10 mg/l and 101.9±1.5% at 800 mg/l (mean±SD, N=3). AMCC was measured in urine from 22 exposed subjects. A strong correlation was found between AMCC and environmental DMF [AMCC (mg/g creatinine)=3.40×DMF (mg/m³)+3.07; r=0.95], while in the urine of 20 unexposed subjects the concentration of AMCC was constantly below the detection limit of the method (0.9 mg/l in urine). The method described appears to be useful for the biological monitoring of DMF exposure.
Inactivation of rat liver cytochrome P450 (P450) by N,N-dimethylformamide and N,N-dimethylacetamide
2001, Toxicology Letters
N,N-dimethylformamide (DMF), an organic solvent widely used in industry, is bioactivated by cytochrome P450 (P450) to reactive metabolites which are believed to be responsible for the hepatotoxicity observed in animals and humans. A decrease of the activating enzyme has been reported in rats treated with DMF, although the specific P450 isoform(s) involved and the nature of the reactive species responsible for this and the other toxic effects are still being investigated. In the present work, the effect of DMF and of the structurally related N,N-dimethylacetamide (DMAc) on the activating enzyme and the nature of the reactive species involved in the mechanism of P450 inactivation by the two chemicals were investigated in vitro. Incubation of liver microsomes from pyridine-induced rats with either substrate resulted in a dose-dependent (0–20 mM) loss of P450 (up to 28 and 24% for DMF and DMAc, respectively), microsomal haem (up to 24 and 20% for DMF and DMAc, respectively), but not protoporphyrin IX content. Moreover, bubbling of CO through the incubation mixture gave almost complete protection against substrate-dependent P450 inactivation, and the spin trapping agent N-tert-butyl-α-phenylnitrone, but neither glutathione nor vitamin C, provided a significant protection against DMF- or DMAc-dependent haem loss. Finally, electron spin resonance analysis of microsomal incubations in presence of DMF or DMAc showed spectral evidence for a carbon centered radical intermediate. The results indicate, overall, that both compounds are metabolized in vitro by P450, probably CYP2E1, to free radical metabolites which attack the haem prosthetic group, leading to suicidal enzyme inactivation.

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Study on in vivo and in vitro metabolism of dimethylformamide in male and female rats

Abstract

Toxicol. Appl. Pharmacol.

Clin. Chim. Acta

J. Biol. Chem.

Metabolism studies of N,N-dimethylformamide. I. Studies in rats and dogs

Int. Arch. Arbeitsmed.

Biological surveillance of workers exposed to dimethylformamide and the influence of skin protection on its percutaneous absorption

Int. Arch. Occup. Environ. Health

Urinary excretion of metabolite following experimental human exposure to dimethylformamide and dimethylacetamide

J. Occup. Med.