Differential induction of estrogen receptors in Cichlasoma dimerus (Teleostei, Perciformes) exposed to octylphenol

GENOVESE, G.; MAGGESE, M. C.; TOWLE, D. W.

Bulletin of the Mount Desert Island Biological Laboratory

Mount Desert Island Biological Laboratory

Lugar: Salsbury Cove, Maine, EEUU; Año: 2008 vol. 47 p. 56 - 57

0097-0883

We have previously shown that octylphenol (OP), a degradation product of alkylphenol polyethoxylates (a group of non-ionic detergents used in several industries, acts as an endocrine disruptor, augmenting the expression of vitelline envelope proteins (VEP) and vitellogenin (VTG) of exposed male Cichlasoma dimerus fish, in a reversible fashion. Unexpectedly, the exposure to the lowest concentration of OP (0.15 ug/L) caused significant induction of VEP (beta, gamma) and VTG as early as day 3 of exposure, similarly to 150 ug/L OP. The other two concentrations of OP (1.5 and 15 ug/L) caused minor non-significant effects. Since the liver, under estrogenic control, synthesizes these proteins, we proposed to study the expression of estrogen receptors (ER) under the same conditions of xenoestrogenicity. ERalpha responded in a manner similar to VEP and VTG, and the effects were reversible. On the contrary, ERbeta2 mRNA expression seemed to be inhibited by the two highest OP concentrations, though this effect was not statistically significant. ERbeta2 gene expression was induced by 1.5 ug/L OP after 6 days of exposure but its expression was reduced on day 21. The lowest OP concentration induced ERbeta2 gene expression over the entire period of exposure, which might explain the induction of VEP and VTG reported before, suggesting that the estradiol-ER complex regulates these genes in a complicated fashion.