title: Impact of an environmental relevant concentration of 17α-ethinylestradiol on the cardiac function of bullfrog tadpoles.
abstract: This study evaluated if a concentration of 17α-ethinylestradiol (EE2 - 10 ng L(-1) for 96 h) normally found in Brazilian surface waters exerts any impact on cardiac function of bullfrog tadpoles (25 Gosner stage), Lithobates catesbeianus. During exposure, the animals' activity level (AL -% of active individuals) was monitored twice a day. Then, the in loco heart rate (f(H) - bpm) was determined, as well as the relative ventricular mass (RVM - % of body mass). Afterwards, cardiac ventricles were mounted for isometric force recordings (CS - mN mm(-2)), and determination of the cardiac pumping capacity (CPC - mN mm(-2) min(-1)). EE2 did not affect tadpoles' AL, although it resulted in a tachycardia in animals exposed to EE2 (f(H) = 66 bpm) when compared to controls (f(H) = 52 bpm), suggesting that EE2 acts directly on the cardiac muscle of tadpoles, rather than being a result of an increased cardiac demand due to a higher activity level (i.e., avoidance response). Additionally, EE2 exerted a positive inotropic response, which resulted in a higher CPC, which occurred independently of an increase in the number of myofibrils of EE2-exposed animals, since RVM remained similar between experimental groups. Thus, the increase on cardiac demand induced by the exposure to EE2 elevates considerably the animal energy expenditure, diverting a large amount of energy that tadpoles could use for their growth and development. These alterations can make amphibians more susceptible to predators and reduce the likelihood to reach reproductive stage.
authors.affiliation: Laboratory of Conservation Physiology, Department of Biology, Federal University of São Carlos, Rodovia João Leme dos Santos (SP-264), Km 110, Sorocaba, São Paulo, Brazil.
authors.forename: Raquel F
authors.initials: RF
authors.lastname: Salla
authors.affiliation: Laboratory of Conservation Physiology, Department of Biology, Federal University of São Carlos, Rodovia João Leme dos Santos (SP-264), Km 110, Sorocaba, São Paulo, Brazil.
authors.forename: Fernando U
authors.initials: FU
authors.lastname: Gamero
authors.affiliation: Laboratory of Conservation Physiology, Department of Biology, Federal University of São Carlos, Rodovia João Leme dos Santos (SP-264), Km 110, Sorocaba, São Paulo, Brazil.
authors.forename: Rafael Z
authors.initials: RZ
authors.lastname: Rissoli
authors.affiliation: Laboratory of Conservation Physiology, Department of Biology, Federal University of São Carlos, Rodovia João Leme dos Santos (SP-264), Km 110, Sorocaba, São Paulo, Brazil.
authors.forename: Samuel E
authors.initials: SE
authors.lastname: Dal-Medico
authors.affiliation: Department of Morphology and Pathology, Pontifical Catholic University of São Paulo, Rua Joubert Wey, 290, Sorocaba, São Paulo, Brazil.
authors.forename: Luciano Mendes
authors.initials: LM
authors.lastname: Castanho
authors.affiliation: Laboratory of Conservation Physiology, Department of Biology, Federal University of São Carlos, Rodovia João Leme dos Santos (SP-264), Km 110, Sorocaba, São Paulo, Brazil.
authors.forename: Cleoni dos Santos
authors.initials: Cdos S
authors.lastname: Carvalho
authors.affiliation: Laboratory of Structural and Functional Biology, Department of Biology, Federal University of São Carlos, Rodovia João Leme dos Santos (SP-264), Km 110, Sorocaba, São Paulo, Brazil.
authors.forename: Elaine C M
authors.initials: EC
authors.lastname: Silva-Zacarin
authors.affiliation: Laboratory of Comparative Physiology and Biochemistry, Department of Physiology, Federal University of São Carlos, Rodovia Washington Luís (SP-310), km 235, São Carlos, São Paulo, Brazil.
authors.forename: Ana L
authors.initials: AL
authors.lastname: Kalinin
authors.affiliation: Laboratory of Structural and Functional Biology, Department of Biology, Federal University of São Carlos, Rodovia João Leme dos Santos (SP-264), Km 110, Sorocaba, São Paulo, Brazil.
authors.forename: Fabio C
authors.initials: FC
authors.lastname: Abdalla
authors.affiliation: Laboratory of Conservation Physiology, Department of Biology, Federal University of São Carlos, Rodovia João Leme dos Santos (SP-264), Km 110, Sorocaba, São Paulo, Brazil. Electronic address: monica@ufscar.br.
authors.forename: Monica J
authors.initials: MJ
authors.lastname: Costa
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D054750:Ecotoxicology; D004777:Environment; D004785:Environmental Pollutants / Q000633:toxicity*; D004997:Ethinyl Estradiol / Q000633:toxicity*; D006321:Heart / Q000187:drug effects* / Q000502:physiology*; D007814:Larva / Q000187:drug effects / Q000502:physiology; D011892:Rana catesbeiana / Q000254:growth & development / Q000502:physiology*; D012098:Reproduction / Q000187:drug effects
chemical_list: D004785:Environmental Pollutants; D004997:Ethinyl Estradiol
keywords: 17α-ethinylestradiol; Bullfrog tadpoles; Cardiac physiology; Lithobates catesbeianus; Xenoestrogens