Potencial estrogênico de metais pesados, xenoestrógenos e estrógenos naturais em peixes neotropicais em condições naturais e experimentais

• Ano de defesa: 2019
• Autor(a) principal: Alessandro Loureiro Paschoalini
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; ICB - INSTITUTO DE CIÊNCIAS BIOLOGICAS; Programa de Pós-Graduação em Biologia Celular; UFMG
• Palavras-chave em Português: Xenoestrógenos; Desregulação endócrina; Gametogênese; Biomarcadores; Peixes; Reprodução
• Link de acesso: http://hdl.handle.net/1843/35356

Fish reproduction, as in other vertebrates, is controlled by the hypothalamic-pituitary-gonadal (HPG) axis. Adequate environmental conditions serve as a "trigger", leading to the release of gonadotrophin releasing hormone (GnRH) acting on the ovaries and testes and then stimulating gonadal maturation and estrogen production as: 17β-estradiol (E2), Testosterone (T), and 11-Ketotestosterone (11-KT). The entry of toxic components into aquatic environments is often related to the generation and disposal of waste from anthropogenic activities. Many of these components, also known as Endocrine Disrupting Chemicals (EDCs), can act in the endocrine system of animals compromising the hormonal synthesis and consequently the reproductive fitness of several species of vertebrates. In order to compare the estrogenic effects of EDCs on neotropical freshwater fish, two types of studies were conducted: (1) a study conducted in a natural environment, where data on the reproduction of commercially important species Prochilodus argenteus; (2) a study conducted under experimental conditions, where adults of Astyanax bimaculatus were exposed for 15 days at the same dosage (10μg/L) of two estrogenic compounds and the mixture of them, in order to comparatively analyze their estrogenic capacity. In both studies, we obtained the morphometric variables of all analyzed fish, such as: total length; body weight, liver weight, gonadal weight, and sex. In addition, the biological indices were calculated and the variations in the levels of estradiol and biomarkers of endocrine disruption and contamination by metals (Vitelogenina, Zona radiata proteins, Estrogen receptors α and β and Metallothionein) were analyzed. The results showed that the animals exposed to contaminants may present altered estradiol levels and variations in the expression of vitellogenin, Zona radiata proteins and metallothionein, when compared to control animals. In addition, several morphological changes in spleen, liver and gonads were described for each treatment. The data of the present study show the endocrine disruption in Prochilodus argenteus in the São Francisco river basin in a pioneering way, and alerts on the consumption of animals contaminated with estrogenic compounds.