Change search
ReferencesLink to record
Permanent link

Direct link
Hemoglobin adducts and micronuclei in rodents after treatment with isoprene monoxide or butadiene monoxide
Stockholm University, Faculty of Science, Department of Environmental Chemistry.
Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Environmental Chemistry.
Responsible organisation
2005 (English)In: Mutation Research, ISSN 1383-5742, Vol. 585, no 1-2, 21-32 p.Article in journal (Refereed) Published
Abstract [en]

1,3-Butadiene and isoprene (2-methyl-1,3-butadiene) are chemically related substances that are carcinogenic to rodents. The overall aim of this work is to elucidate the role of the genotoxic action of diepoxide metabolites in the carcinogenesis of the dialkenes. In vivo doses of the diepoxide metabolites were measured through reaction products with hemoglobin (Hb adducts) in studies of induced micronuclei (MN) in rodents. In the reaction with N-terminal valine in Hb, diepoxybutane and isoprenediepoxide form ring-closed adducts, pyrrolidines [N,N-(2,3-dihydroxy-1,4-butadiyl)valine and N,N-(2,3-dihydroxy-2-methyl-1,4-butadiyl)valine, respectively]. The method applied for Hb-adduct measurement is based on tryptic degradation of the protein and liquid chromatography electrospray ionisation tandem mass spectrometry (LC–ESI-MS/MS) analysis. Mice were given single i.p. injections of the monoepoxides of butadiene and isoprene, 1,2-epoxy-3-butene or 1,2-epoxy-2-methyl-3-butene, respectively. Rats were treated in the same way with 1,2-epoxy-3-butene. In mice pyrrolidine adduct levels increased with increasing administered doses of the monoepoxides. The in vivo dose of diepoxybutane was on average twice as high (0.29 ± 0.059 mMh) as the in vivo dose of isoprenediepoxide (0.15 ± 0.053 mMh) per administered dose (mmol/kg body weight) of the monoepoxides. In mice the genotoxic effects of the two monoepoxides, measured as the increase in the frequencies of micronuclei (MN), were approximately linearly correlated to the in vivo doses of the diepoxides (except at the highest dose of diepoxybutane). In rats the pyrrolidine-adduct levels from diepoxybutane were below the limit of quantification at all administered doses of 1,2-epoxy-3-butene and no significant increase was observed in the frequency of MN. Measurement of the ring-closed adducts to N-termini in Hb by the applied method permits analysis of in vivo doses of diepoxybutane and isoprenediepoxide, which may be further used for the elucidation of the mechanisms of carcinogenesis of butadiene and isoprene.

Place, publisher, year, edition, pages
Elsevier B.V. , 2005. Vol. 585, no 1-2, 21-32 p.
Keyword [en]
Isoprene; Butadiene; Metabolites; LC–MS; Micronucleus; Hemoglobin adduct
National Category
Environmental Sciences
URN: urn:nbn:se:su:diva-25173DOI: 10.1016/j.mrgentox.2005.03.009OAI: diva2:199061
Part of urn:nbn:se:su:diva-78Available from: 2004-03-25 Created: 2004-03-25 Last updated: 2010-09-14Bibliographically approved
In thesis
1. Methods for measurement of reactive metabolites as a basis for cancer risk assessment: Application to 1,3-butadiene and isoprene
Open this publication in new window or tab >>Methods for measurement of reactive metabolites as a basis for cancer risk assessment: Application to 1,3-butadiene and isoprene
2004 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

1,3-Butadiene is a general air pollutant associated with combustion of organic matter and is also an extensively used monomer in polymer production. The cancer risk estimation of 1,3-butadiene is encumbered with large uncertainties. Extrapolation from tumour frequencies in long-term animal tests has led to a relatively high figure for the risk associated with 1,3-butadiene exposure. This is mainly based on observations of very high tumour incidences in butadiene-exposed mice, which in this respect are about 100 times more sensitive than rats. It has been hypothesized that a high cancer risk from 1,3-butadiene could be associated with its metabolism to the bifunctional 1,2:3,4-diepoxybutane (DEB) which, in comparison with monofunctional epoxides, 1,2-epoxy-3-butene (EB) and 1,2-epoxy-3,4-butanediol (EBdiol), is a highly effective mutagen, i.e. cancer initiator. Measurement of in vivo doses of DEB is therefore essential for the risk assessment of 1,3-butadiene. Reaction products with hemoglobin offer a possibility of measuring reactive metabolites in vivo. Hemoglobin adducts from EBdiol have in this study been measured with available methods, which are, however, not applicable to the bifunctional DEB, and method development was therefore needed.

This work presents a procedure for measurement of a specific, ring-closed adduct, Pyr-Val, formed from the reaction of DEB with N-terminal valines in hemoglobin. It is based on LC-ESI-MS/MS analysis of the Pyr-modified N-terminal peptides enriched after trypsin digestion of globin. Mouse and rat could be compared regarding the metabolism of EB, DEB and EBdiol. From the data it was concluded that, in 1,3-butadiene exposure, about 60 times higher levels of DEB are formed in mice compared to rats. Estimates of in vivo doses in published cancer tests showed that carcinogenesis in mice is mainly due to DEB, whereas in rat, and possibly man, the monofunctional EBdiol is the predominant causative factor. Preliminarily, the cancer risk assessed from these data is compatible with the epidemiology-based risk estimate of US EPA.

Due to the structural similarity with 1,3-butadiene, certain parallel studies of isoprene (2-methyl-1,3-butadiene) metabolism were initiated. Isoprene is the major endogenously produced hydrocarbon in humans and mammals and shows a similar difference in sensitivity between species for tumour development as 1,3-butadiene. In mice treated with the isoprene monoepoxide, 1,2-epoxy-2-methyl-3-butene (IMO), an in vivo formation of the corresponding diepoxide, 1,2:3,4-diepoxy-2-methyl-butane (IDO), was demonstrated. The in vivo dose of IDO formed from IMO was about half of that of DEB formed from EB. In the analysis of bone marrow erythrocytes an increased frequency of micronuclei, induced by treatment with EB or IMO, showed correlation with the in vivo doses of the respective diepoxides.

With the ambition to reduce animal experiments a general procedure has been developed for trapping reactive metabolites in in vitro test systems, with the specific aim to study differences between species in metabolism of 1,3-butadiene. Vitamin B12 in its reduced form [Cbl(I)] has been used for instant trapping of 1,3-butadiene metabolites formed in S9-mixture. LC-ESI-MS/MS is then used for quantification of the formed alkyl-Cbls. The method has been applied to the epoxide metabolites of 1,3-butadiene, which all form specific alkyl-Cbls in the reaction with Cbl(I)

Place, publisher, year, edition, pages
Stockholm: Institutionen för miljökemi, 2004. 84 p.
National Category
Environmental Sciences
urn:nbn:se:su:diva-78 (URN)91-7265-840-1 (ISBN)
Public defence
2004-04-15, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 12 A, Stockholm, 13:00
Available from: 2004-03-25 Created: 2004-03-25Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Törnqvist, Margareta
By organisation
Department of Environmental ChemistryEnvironmental Chemistry
In the same journal
Mutation Research
Environmental Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 55 hits
ReferencesLink to record
Permanent link

Direct link