title: Altered hepatic retinol and CYP26 levels in adult European common frogs (Rana temporaria) exposed to p,p'-DDE.
abstract: The effects of environmental contamination on amphibians are of particular concern because there are reports of declining numbers of species and individuals in most parts of the world during the last 50 years. During the last decade there has been increased focus on the role of persistent organic pollutants as retinoid (vitamin A) disrupters, and their effects on development, growth and sexual differentiation. To study the effects of p,p'-DDE, one of the most persistent metabolites of the pesticide DDT, on retinol homeostasis, we subcutaneously exposed adult male European common frogs (Rana temporaria) to different doses of p,p'-DDE (0, 0.01, 0.1, 1 and 10 mg/kg body mass) and studied the effect of a short term exposure (14 days) on hepatic retinoid levels and CYP26 gene and protein expression. Hepatic retinol concentrations, CYP26 gene and protein levels were analysed using HPLC, quantitative RT-PCR and indirect ELISA, respectively. Our results showed a significant p,p'-DDE dose-specific increase in the hepatic retinol concentration. CYP26 gene and protein expression were reduced in an apparent p,p'-DDE dose-specific manner. The results suggest that p,p'-DDE may interfere with the hepatic metabolism of retinol in adult frogs by decreasing CYP26 expression patterns.
authors.affiliation: Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway. angels_levia_presa@yahoo.es
authors.forename: Angels
authors.initials: A
authors.lastname: Leiva-Presa
authors.forename: Anne Skjetne
authors.initials: AS
authors.lastname: Mortensen
authors.forename: Augustine
authors.initials: A
authors.lastname: Arukwe
authors.forename: Bjørn Munro
authors.initials: BM
authors.lastname: Jenssen
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003577:Cytochrome P-450 Enzyme System / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D003633:Dichlorodiphenyl Dichloroethylene / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000633:toxicity*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D007306:Insecticides / Q000633:toxicity*; D008099:Liver / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology; D008297:Male; D011896:Rana temporaria / Q000502:physiology*; D000072516:Retinoic Acid 4-Hydroxylase; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014801:Vitamin A / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D004785:Environmental Pollutants; D007306:Insecticides; D014801:Vitamin A; D003633:Dichlorodiphenyl Dichloroethylene; D003577:Cytochrome P-450 Enzyme System; D000072516:Retinoic Acid 4-Hydroxylase