title: In vitro assessment of endocrine disrupting potential of naphthenic Acid fractions derived from oil sands-influenced water.
abstract: Oil sands-influenced process waters have been observed to cause reproductive effects and to induced CYP1A activity in fishes; however, little progress has been made in determining causative agents. Naphthenic acids (NAs) are the predominant organic compounds in process-affected waters, but due to the complexity of the mixture, it has been difficult to examine causal linkages in fishes. The aim of this study was to use in vitro assays specific to reproductive and CYP1A mechanisms to determine if specific acid extractable fractions of NAs obtained from oil sands-influenced water are active toward reproductive processes or interact with the Ah receptor responsible for CYP1A activity. NAs were extracted from aged oil sands-influenced waters by use of acid precipitation, and the mixture was fractionated into three acidic and one neutral fraction. The four fractions were examined for Ah receptor-mediated potency by use of the H4IIE-luc bioassay, effects on production of steroid hormones by use of the H295R steroidogenesis assay, and sex steroid receptor binding activity using the yeast estrogen screen and yeast androgen screen. The mixtures were characterized by high resolution mass spectrometry, (1)H nuclear magnetic resonance, and attenuated total reflectance infrared spectroscopy. The neutral fraction elicited Ah-receptor mediated activity after 24 h but not after 48 or 72 h. None of the fractions contained measurable levels of estrogen or androgen receptor agonists nor did they cause reductions in steroidogenesis. A number of fractions showed antiestrogenic or antiandrogenicity potency, with the neutral and main acidic fractions being the most potent. Neutral aromatic compounds are likely responsible for the CYP1A activity observed. Direct estrogenic, androgenic, or steroidogenic mechanisms are unlikely for NAs based on these results, but NAs act as potent antiandrogen or antiestrogens.
authors.affiliation: †Canadian Rivers Institute, University of Prince Edward Island, Charlottetown, Prince Edward Island C1A 4P3, Canada.
authors.forename: Liane A
authors.initials: LA
authors.lastname: Leclair
authors.affiliation: ‡Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada.
authors.forename: Lani
authors.initials: L
authors.lastname: Pohler
authors.affiliation: ‡Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada.
authors.forename: Steve B
authors.initials: SB
authors.lastname: Wiseman
authors.affiliation: ‡Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada.
authors.forename: Yuhe
authors.initials: Y
authors.lastname: He
authors.affiliation: †Canadian Rivers Institute, University of Prince Edward Island, Charlottetown, Prince Edward Island C1A 4P3, Canada.
authors.forename: Collin J
authors.initials: CJ
authors.lastname: Arens
authors.affiliation: ‡Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada.|§Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B4, Canada.
authors.forename: John P
authors.initials: JP
authors.lastname: Giesy
authors.affiliation: ⊥Department of Chemistry, University of Prince Edward Island, Charlottetown, Prince Edward Island C1A 4P3, Canada.
authors.forename: Stephen
authors.initials: S
authors.lastname: Scully
authors.affiliation: ⊥Department of Chemistry, University of Prince Edward Island, Charlottetown, Prince Edward Island C1A 4P3, Canada.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Wagner
authors.affiliation: †Canadian Rivers Institute, University of Prince Edward Island, Charlottetown, Prince Edward Island C1A 4P3, Canada.
authors.forename: Michael R
authors.initials: MR
authors.lastname: van den Heuvel
authors.affiliation: ‡Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada.|∥Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5A8, Canada.
authors.forename: Natacha S
authors.initials: NS
authors.lastname: Hogan
mesh_terms: D000728:Androgens / Q000032:analysis; D000818:Animals; D001681:Biological Assay; D002264:Carboxylic Acids / Q000032:analysis*; D005591:Chemical Fractionation; D052244:Endocrine Disruptors / Q000032:analysis* / Q000633:toxicity; D004967:Estrogens / Q000032:analysis; D006801:Humans; D061329:Oil and Gas Fields; D000072317:Polychlorinated Dibenzodioxins / Q000032:analysis; D066244:Proton Magnetic Resonance Spectroscopy; D051381:Rats; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism; D012015:Reference Standards; D012987:Soil / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity
chemical_list: D000728:Androgens; D002264:Carboxylic Acids; D052244:Endocrine Disruptors; D004967:Estrogens; D000072317:Polychlorinated Dibenzodioxins; D018336:Receptors, Aryl Hydrocarbon; D012987:Soil; D014874:Water Pollutants, Chemical; D014867:Water; C046170:naphthenic acid