title: Migration of phthalates on culture plates - an important challenge to consider for in vitro studies.
abstract: Phthalates are endocrine disruptors of the reproductive system and suspected to influence many other organ and hormone systems. They are also semi-volatile organic compounds present in the gas phase in the environment. Their mode of action has been investigated in numerous in vitro studies. Multi-well culture plates are typically used to study phthalates in cell cultures. In a pilot study, we observed evidence of phthalate migration in 24-well culture plates. As this has not previously been described, we investigated the phenomenon in more detail. Primary human thyroid epithelial cell cultures (n = 8 cultures) were exposed to either di-ethyl phthalate (DEP), di-n-butyl phthalate (DnBP), mono-n-butyl phthalate (MnBP) or di-(2-ethylhexyl) phthalate (DEHP). Measurement of phthalate metabolites by mass spectrometry demonstrated that the short-branched DEP was able to migrate to adjacent wells when added to cell culture plates. DnBP also seemed to be able to migrate, unlike the long-branched DEHP or the monoester MnBP which did not seem to have this ability. High background levels of phthalate metabolites were also observed, which might compromise results from low dose phthalate studies. In conclusion, the migration of phthalates which is probably caused by their volatile properties might lead to false interpretation of study results.
authors.affiliation: a Department of Medical Endocrinology , Rigshospitalet, University of Copenhagen , Denmark ;
authors.forename: Juliana
authors.initials: J
authors.lastname: Frohnert Hansen
authors.affiliation: b Department of Growth and Reproduction , Rigshospitalet, University of Copenhagen , Denmark.
authors.forename: Malene
authors.initials: M
authors.lastname: Boas
authors.affiliation: a Department of Medical Endocrinology , Rigshospitalet, University of Copenhagen , Denmark ;
authors.forename: Marianne
authors.initials: M
authors.lastname: Møller Brorson
authors.affiliation: b Department of Growth and Reproduction , Rigshospitalet, University of Copenhagen , Denmark.
authors.forename: Hanne
authors.initials: H
authors.lastname: Frederiksen
authors.affiliation: a Department of Medical Endocrinology , Rigshospitalet, University of Copenhagen , Denmark ;
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Hartoft-Nielsen
authors.affiliation: a Department of Medical Endocrinology , Rigshospitalet, University of Copenhagen , Denmark ;
authors.forename: Åse
authors.initials: Å
authors.lastname: Krogh Rasmussen
authors.affiliation: b Department of Growth and Reproduction , Rigshospitalet, University of Copenhagen , Denmark.
authors.forename: Katharina M
authors.initials: KM
authors.lastname: Main
authors.affiliation: a Department of Medical Endocrinology , Rigshospitalet, University of Copenhagen , Denmark ;
authors.forename: Ulla
authors.initials: U
authors.lastname: Feldt-Rasmussen
mesh_terms: D018929:Cell Culture Techniques / Q000295:instrumentation; D002478:Cells, Cultured; D052244:Endocrine Disruptors / Q000032:analysis / Q000737:chemistry* / Q000494:pharmacology; D004847:Epithelial Cells / Q000187:drug effects / Q000502:physiology; D006801:Humans; D010795:Phthalic Acids / Q000032:analysis / Q000737:chemistry* / Q000494:pharmacology; D010865:Pilot Projects; D061251:Primary Cell Culture; D013961:Thyroid Gland / Q000166:cytology; D014835:Volatilization
chemical_list: D052244:Endocrine Disruptors; D010795:Phthalic Acids; C007379:diethyl phthalate; C028577:monobutyl phthalate
keywords: Primary cell cultures; chromatography; dibutyl phthalate; diethyl phthalate; diethylhexyl phthalate; plasticizers; tandem mass spectrometry; volatilization