Vitelline envelope proteins and vitellogenin gene expression in Cichlasoma dimerus (Teleostei, Perciformes) exposed to octylphenol.

REGUEIRA, M.; LO NOSTRO, F. L.; TOWLE, D. W.; MAGGESE, M. C.; GRISELDA GENOVESE

Montevideo, Uruguay

Congreso; VIII Congreso SETAC LA "Ecotoxicologia y desarrollo sustentable"; 2007

Facultad de Ciencias. Universidad de la Republica

Endocrine disrupting chemicals have become ubiquitous in the environment and adversely affect physiology by interfering with normal endocrine functions. Octylphenol (OP) is a degradation product of non-ionic detergents mainly used in industrial applications, which can cause reproductive impairments acting as xenoestrogens. Our previous results showed that in Cichlasoma dimerus, vitelline envelope proteins (VEP) and vitellogenin (VTG) are synthesized by liver of mature females under estrogenic control but are never produced by normal males. It was also demonstrated that exposure of male fish to 150 µg/L OP strongly induced the expression of VEP after 1 day of treatment. The aim of the present study was to assess the effect of environmentally relevant concentrations of OP on mRNA expression of VTG and VEP and the reversibility of the effect. C. dimerus males were exposed to 150, 15, 1.5, and 0.15 µg/L 4-(tert-octyl)phenol 97% (Aldrich) for 0-28 days. Livers were preserved in cold RNAlater for RNA extraction. Species-specific primers designed to target VEP and VTG were used to quantify mRNA expression. Exposure of male fish to 0.15 µg/L OP caused significant induction of liver VEP mRNA (â, ã) and VTG mRNA on day 3 of exposure. The other two concentrations of OP used (1.5 and 15 µg/L) caused minor non-significant effects. Expression of the genes studied diminishes upon transference to OP-free water. We conclude that the feminizing effects caused by OP are reversible and that VEP and VTG gene expression is a sensitive method to monitor OP exposure. Key words: octylphenol, vitellogenin, vitelline envelope proteins, fish.