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PubMed1991

Urinary excretion of ethylenethiourea and kidney morphology in rats after continuous oral exposure to nabam or ethylenethiourea.

Nabam, an ethylenebisdithiocarbamate (EBDC), is an agricultural fungicide. Ethylenethiourea (ETU), widely used in the rubber industry, is a degradation and byproduct of metabolism and of storage and production of EBDCs. Kidney function and morphology, and urinary excretion of ETU, were studied in rats exposed to nabam or ETU in drinking water for 28 days. The concentrations of nabam in drinking water were 0, 50, 100 or 200 mg/l, and of ETU 0, 100, 200 or 300 mg/l. Both compounds decreased body weight gain but did not significantly affect urinary sodium, potassium, glucose, or protein excretion, or urinary osmolality. Urinary vasopressin was also unaltered after exposure to nabam or ETU. High doses of ETU resulted in ultrastructural alterations in epithelial cells of renal proximal tubuli. ETU was excreted in urine after exposure to both nabam and ETU. There seemed to be a threshold dose of ETU below which no ultrastructural alterations in kidney occurred.

Administration, Oral↗

PubMed1978

Induction of dominant-lethal mutations after administration of ethylenethiourea in combination with nitrite of the n-nitroso-ethylenethiourea in mice.

Mutagenic potentials of ethylenethiourea (ETU) in combination with sodium nitrite or of N-nitroso-ETU, a nitrosation product of ETU in vitro, were investigated in the mouse dominant-lethal test. Simultaneous 5-day p.o. administration of ETU (150 mg/kg) and sodium nitrite (50 mg/kg) caused a significant decrease in the percentage pregnancy and the number of implants in weeks 5 and 6 of testing, although no effects were obtained on these indices when the chemicals were applied separately. However, in the group treated with 30 mg ETU plus 10 mg sodium nitrite per kg no dominant-lethal mutations were induced. 5-day oral administration of 100 mg of N-nitroso-ETU per kg also exhibited similar effects to those observed after treatment with 150 mg ETU plus 50 mg sodium nitrite per kg.

Animals↗

PubMed1997

Degradation of ethylenethiourea (ETU) in oxic and anoxic sandy aquifers.

Ethylenethiourea is an important degradation product of ethylenebisdithiocarbamate fungicides, which are widely used in different kinds of crops. The ethylenebisdithiocarbamate group includes maneb, zineb and mancozeb. The ethylenebisdithiocarbamates are not highly toxic and degrade rapidly in the presence of moisture and oxygen, forming different compounds. One of these is the polar ethylenethiourea, which is relatively stable. Thus, this compound appears to be a potential contaminant for groundwater. Batch experiments were carried out under biotic as well as abiotic conditions to study the degradation dependence of concentration, temperature and organic matter. The decomposition of ethylenethiourea under abiotic conditions was found to be less than 5% of the degradation under biotic conditions. Further, ethylenethiourea showed to be stable over a period of 150 days at 20 degrees C in tap water as well as in batch with soil sterilized with NaN3. The degradation of ethylenethiourea depends on the concentration in the water implying first order reaction kinetics. The microbial degradation of ethylenethiourea is highly temperature dependent with aerobic Q10 between 2.9 and 4.2, and an anaerobic between 2.1 and 2.5. A minor increase in degradation rates was observed by application of nitrate and manure to the batches. The experiments show extremely complete degradation of ethylenethiourea in the presence of microbial nitrate reduction with pyrite which occurs in deeper parts of the aquifers.

Antifungal Agents↗

PubMed1991

Species differences between rats and mice in the teratogenic action of ethylenethiourea: in vivo/in vitro tests and teratogenic activity of sera using an embryonic cell differentiation system.

In vivo/in vitro studies on rats showed that ethylenethiourea inhibited the differentiation of midbrain cells more severely than that of limb bud cells. In in vitro studies using midbrain cell cultures, ethylenethiourea concentrations inhibited the production of differentiated foci by 50% in mouse cells, a rate 11-fold higher than that in rat cells. Differentiation of rat midbrain cells was also inhibited by the serum samples prepared from rats or mice dosed with up to 200 mg/kg of ethylenethiourea. However, differentiation of mouse cells was not inhibited by these animal serum samples. The concentration of ethylenethiourea in rat sera was only 2-fold higher than that in mice sera at 2 hr after dosing with 200 mg/kg. Therefore, the different sensitivity of the midbrains of these two species may be one reason that ethylenethiourea is teratogenic in rats but not in mice.

Animals↗

PubMed1998

An assay system for detecting environmental toxicants with cultured cladoceran eggs in vitro: malformations induced by ethylenethiourea.

An in vitro assay system using cladoceran eggs was developed for the detection of toxic compounds in the aquatic environment. Parthenogenetic eggs of Daphnia magna were removed from the brood chambers of female adults and cultured individually in 96-well microtiter plates with Elendt M7 medium at 23 degrees C. Embryonic development proceeded completely in vitro with more than 95% hatchability. Egg development time in vitro was 2 days, which was almost equal to that in the brood chamber of the mother. Ethylenethiourea, a compound teratogenic to mammals, was investigated for toxicity to development of eggs. Isolated eggs were cultured in the presence of ethylenethiourea during the period of embryonic development for 3 days. Treatment with ethylenethiourea induced morphological abnormalities in the cladoceran carapace. Parthenogenetic eggs of Cladocera are genotypically identical, which makes them useful biological materials for a toxicity test on aquatic pollutants.

Animals↗

PubMed1982

The effect of oxidation of the sulfur atom on the mutagenicity of ethylenethiourea.

Ethylenethiourea is metabolized in mice by oxidation of the sulfur atom to form 2-imidazolin-2-yl sulfenate. Ethylenethiourea itself is a carcinogen, goitrogen, teratogen and a weak bacterial mutagen. The mutagenicities of ethylenethiourea, 2-imidazolin-2-yl sulfenate and their nitroso derivatives were compared in direct bacterial tests and in the host-mediated assay. In all the test systems applied, 2-imidazolin-2-yl sulfenate was less mutagenic than the parent compound.

Ethylenethiourea↗

PubMed2004

[Using the FRTL-5 cell to screen the thyroxine disrupting effects of the two pesticides-ethylenethiourea and pendimethalin].

OBJECTIVE: In order to study the effects of ethylenethiourea(ETU) and pendimethalin on synthesis and secretion of thyroglobulin(Tg) in FRTL-5 cells in vitro. METHODS: MTT test was used to investigate the cytotoxicity of the two chemicals to FRTL-5 cell. When the concentration of pendimethalin exceeded 5 ng/microliter, and the concentration of ethylenethiourea exceeded 360 ng/microliter, there was distinct cytotoxicity to FRTL-5 cell. The radioimmunoassay was also used to detect the level of thyroglobulin in culture. The exposure doses in radioimmunoassay was based on the MTT test. RESULTS: The concentration of Tg was decreased in medium and high dose of pendimethalin and ethylenethiourea. CONCLUSION: It is likely, therefore, that the two pesticides might disrupt FRTL-5 cell of synthesizing and secreting Tg.

Aniline Compounds↗

PubMed1981

Effects of pretreatment with SKF-525A, N-Methyl-2-thioimidazole, sodium phenobarbital, or methyl cholanthrene on ethylenethiourea-induced teratogenicity in rats.

SKF-525A (SKF), a well known inhibitor of P450 function, and N-methyl-2 thioimidazole (MMI), an antithyroid drug resembling ethylenethiourea, were tested at the respective dosages of 40 Mg/kg ip and 200 mg/kg po, for their individual or combined effect on the teratogenicity on an oral dose of 60 mg/kg ethylenethiourea (ETU). All chemicals were dissolved in distilled water and administered to rats on the 13th day of pregnancy. MMI and ETU were dosed simultaneously, one hour after dosing with SKF. Control groups were given equivalent doses of ETU (positive control), SKF, MMI, or SKF+MMI. Term fetuses were evaluated for anomalies according to the established procedures. No teratogenic activity was attributed to treatments with SKF, or MMI, of their combination. However, in the remaining test groups, MMI+SKF+ETU+, or SKF+ETU, the type, incidence, and intensity of anomalies, compared to the group given only ETU, were markedly increased and were similar to those previously reported to occur at 120 mg/kg or higher doses of ETU. Pretreatment with either 40, 60, or 80 mg/kg of sodium phenobarbital injected once or twice a day on days 9-12 of pregnancy, or 20 mg/kg/day of methylcholanthrene on days 11-13 of pregnancy, failed to alter significantly the teratogenicity of a subsequent dose of 60 mg/kg of ETU given orally on the 13th day of pregnancy.

Animals↗

PubMed2005

Application of gas chromatography-mass spectrometry for the determination of urinary ethylenethiourea in humans.

Ethylenethiourea (ETU) is a major metabolite of ethylenebisdithiocarbamate pesticides: a sensitive and specific assay for its determination in human urine is proposed below. ETU is extracted on a diatomaceous earth column using dichloromethane and derivatized with the mixture of N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide and tert-butyldimethyilsilyl chloride. The derivative is analyzed using GC/MS in the EI/SIM mode. The whole procedure is carried out in the presence of ethylenethiourea-d(4) as internal standard. The analytical features of the method are: high specificity, >90% recovery, range of linearity 0-200 microg/L, within- and between-run precision as coefficient of variation, <17 and <20%, respectively, limit of quantification 2 microg/L. In specimens stored in the dark at -20 degrees C ETU is stable for at least 6 months. The procedure was successfully applied to the biological monitoring of vineyard workers exposed to EBDTC and of a matched group of subjects from the general population.

Ethylenethiourea↗

PubMed2006

Sonic hedgehog, BMP4, and Hox genes in the development of anorectal malformations in Ethylenethiourea-exposed fetal rats.

BACKGROUND: shh signaling pathway has been shown to be involved in the morphogenesis of many organ systems. In this study, we investigated the expression of shh and its targets, BMP4 and Hox genes, in the development of anorectal malformations in Ethylenethiourea (ETU)-exposed embryos. METHODS: We used ETU murine model of the vertebral, anal, cardiac, tracheoesophageal, renal, and limb association. Ethylenethiourea 1% (125 mg/kg) was given to the pregnant females via gavage feeding on gestational day (gD) 10 and saline to control animals. Embryos were collected at gD12 to gD16 and gD21; hindguts were dissected and snap frozen. Highly purified RNA was isolated, and expression of shh, BMP4, Hoxa13, and Hoxd13 genes was confirmed with RT-PCR. Relative quantitative expression of shh and target genes at each time point was done with SYBR Green I qPCR. Normalized gene of interest expression was calculated by geNorm, and data analysis was done with 2-tail Student t test. RESULTS: shh, BMP4, Hoxa13, and Hoxd13 transcripts were detected in all samples, confirming that shh cascade is active during the process of hindgut development in fetal rats. Relative quantitation demonstrated that shh cascade expression shows time-dependent changes in the developing hindgut. CONCLUSION: This study shows that ETU disturbs the expression of shh signaling pathway during the development of hindgut. We provide evidence that shh plays a pivotal role in the hindgut morphogenesis, and its misexpression affect the expression of targets, BMP4 and Hox genes.

Anal Canal↗

PubMed1997

Liquid chromatography with ultraviolet absorbance detection of ethylenethiourea in blood serum after microwave irradiation as an auxiliary cleanup step.

The report describes a method of deproteinizing serum that combines the action of acids with microwave irradiation. The acid concentration is ten times smaller than in the usual acid deproteinization method and the results are similar. The main advantages of the proposed method are the maintenance of the pH of the supernatant at around 5, and the reduction of the concentration of the deproteinizing agent. The procedure was applied to the determination of ethylenethiourea in serum samples by HPLC with spectrophotometric detection. Using 0.5 ml of serum, 0.04 microgram of ethylenethiourea were determined with recoveries between 89 and 109%.

Carcinogens↗

PubMedDate not supplied

Measurement of ethylenethiourea using thermospray liquid chromatography-mass spectrometry.

Reliable measurement of ethylenethiourea (ETU) is important because ETU is a potent thyroid carcinogen. A method for the separation and identification of ethylenethiourea (ETU) by applying reversed-phase high-pressure liquid chromatography (HPLC) followed by thermospray (TSP) mass spectrometry (MS) detection is described. Single ion recording detection applying HPLC-MS of ETU appeared to be highly selective and equally sensitive as an HPLC method applying UV detection reported in our earlier study (1). The detection limit for ETU was 100 pg per injection.

Chromatography, High Pressure Liquid↗

PubMed1976

(14C)Ethylenethiourea: distribution, excretion, and metabolism in pregnant rats.

Following administration of single oral doses of [14C]ethylenethiourea (ETU) to pregnant rats maternal blood maintained peak radioactivity for 2 h, and the radioactivity was dispersed uniformly between the red blood cells and plasma. The level of radioactivity was distributed equally among several maternal tissues but was present in lower amounts in embryos. Twenty-four hours after treatment all tissues examined, except blood, were relatively clear of radioactivity and 72.8% of the total radioactivity given had been excreted in the urine. Elution patterns of metabolites from Sephadex separation suggested that ethylenethiourea was degraded very little. The teratological mechanism is discussed.

Animals↗

PubMed2003

Analytical method for the quantitative determination of urinary ethylenethiourea by liquid chromatography/electrospray ionization tandem mass spectrometry.

A direct, rapid and selective method for the quantitative determination of the ethylenethiourea (ETU) in human urine has been validated and is reported in the present study. It allows the accurate quantification of ETU in this complex matrix without the use of any internal standard as the sample cleanup is effective enough for the removal of interferences that could lead to ion suppression in the electrospray ionization (ESI) source. This simple and rapid purification system, based on the use of a Fluorosil phase of a BondElut column followed by a liquid-liquid extraction procedure, achieves mean extracted recoveries, assessed at three different concentrations (2.5, 10.0, and 25.0 microg/L), always more than 85%. High-performance liquid chromatography (HPLC) with positive ion tandem mass spectrometry, operating in selected multiple reaction monitoring (MRM) mode, is used to quantify ETU in human urine. The assay is linear over the range 0-50 microg/L, with a lower limit of quantification (LOQ) of 1.5 microg/L and a coefficient of variation (CV) of 8.9%. The lower limit of detection (LOD) is assessed at 0.5 microg/L. The overall precision and accuracy were determined on three different days. The values for within- and between-day precision are < or = 8.3 and 10.1%, respectively, and the accuracy is in the range 97-118%. The relative uncertainties for the LOQ and QC concentrations have been estimated to be 18 and 8%, respectively. The assay was applied to quantify ETU in human urine from growers that regularly handle ethylenebisdithiocarbamate pesticides in large crop plantations. The biological samples were collected at the start and end of the working day, and the ETU urine levels were found to vary between 1.9 and 8.2 microg/L.

Chromatography, Liquid↗

PubMed1977

A comparison of the distribution, metabolism and excretion of ethylenethiourea in the pregnant mouse and rat.

Pregnant mice and rats were treated by stomach intubation on day 15 g of gestation with 240 mg/kg of ethylenethiourea (ETU) made up in part with radiolabeled ETU. Animals were sacrificed at specific times post-treatment, and maternal tissues, fetus, urine and feces were collected for determination of radioactivity. Maternal and fetal tissue levels of ETU were similar at three hours post treatment; thereafter, the mouse (maternal and fetus) showed much less ETU than the rat. The t1/2 of ETU elimination from the maternal blood was 9.4 and 5.5 hours for the rat and mouse, respectively. Analysis of urine by thin-layer chromatography and radiochromatography revealed that the mouse and rat metabolized ETU by different pathways. Furthermore, the mouse is able to metabolize ETU to a greater extent than the rat.

Animals↗

PubMed1978

Teratogenicity of ethylenethiourea and thyroid function in the rat.

Ethylenethiourea (ETU) was given by gavage at a dose of 40 mg/kg/day from Days 7 through 15 of gestation to hypothyroid and euthyroid rats, and to rats given exogenous thyroxine, to determine whether ETU teratogenicity occurs through alteration of maternal thyroid function. At sacrifice on Day 20 of gestation 84-100% of the fetuses in all groups given ETU were malformed regardless of the thyroid status of the dams. Ten percent of the fetuses of dams thyroparathyroidectomized at 75 days of age that were not given ETU were malformed; no malformations were noted among the fetuses of the other groups not given ETU. Hence, ETU was found to induce teratogenicity in rats but not through alteration of maternal thyroid status. In addition, it was determined that ETU lowered serum thyroxine concentration, that hypothyroidism itself increased the background level of malformations in the rat, and that hypothyroidism qualitatively and quantitatively increased the incidence of specific malformations after ETU administration.

Animals↗

PubMed1980

Teratogenic effects of combined administration of ethylenethiourea and nitrite in mice.

Teratogenic potential of ethylenethiourea (ETU) was investigated in SLC-ICR mice after its reaction with sodium nitrite. ETU was given orally in doses of 400 mg/kg on various days of pregnancy in combination with 200 mg/kg NaNO2 at varied intervals. When NaNO2 was given to females immediately after their treatment with ETU on day 6 or 8 of pregnancy, fetal survival was significantly decreased. Various types of malformations were observed in the living fetuses from mothers treated on day 6, 8, or 10 of pregnancy, but not on day 12. The teratogenicity disappeared when NaNO2 was given 2 h after the treatment with ETU.

Abnormalities, Drug-Induced↗

PubMed1987

In vitro teratogenicity of ethylenethiourea in the rat.

We have demonstrated that ethylenethiourea (ETU) is a potent teratogen to the rat embryo developing in vitro. Sprague Dawley rat embryos were explanted on gestation day 10 and cultured for 48 hours in the presence of 40-200 micrograms/ml ETU. This resulted in a dose-related inhibition of growth and differentiation as assessed by crown-rump length, protein and DNA content, and somite number and in an increase in the frequency of abnormalities. A variety of anomalies was produced, including fluid accumulation in the brain (hydrocephalus), decreased mandibular size, decreased telencephalon size, abnormal dorsiflexion, as well as subectodermal blisters on the tail and limb buds and maxilla. Frank malformations have been observed at these same sites--hydrocephalus, brachygnathia, kyphosis, limb and tail defects, cleft palate--in the term fetus in vivo. The presence of abnormal fluid accumulation in the embryos--distended neural tube and subectodermal blisters--suggesting that the osmotic environment of the embryo had been altered by ETU exposure. Osmolality of the exocoelomic fluid (ECF) surrounding the embryo was measured after 48 hours of exposure to a concentration of ETU that caused nearly a 100% incidence of subectodermal blisters. ECF osmolality was found to be significantly lower than that of control embryos. Lowered osmolality would cause water to move out of the ECF, presumably causing the observed fluid accumulation in the embryo. It is speculated that altered osmotic balance and localized edema in the embryo are contributory steps in the formation of defects after ETU exposure.

Abnormalities, Drug-Induced↗