Endocrine disruption by environmental estrogens and its effect on the reproductive success of zebrafish (Danio rerio)
2004
Paraso, M.G.V.(Philippines Univ. Los Baños, College, Laguna (Philippines). Dept. of Basic Veterinary Sciences)
An increasing number of reports on reproductive disturbances brought about by substances in the environment that mimic the activity of the endogenous hormone, 17 Leta-estradiol, have been reported in the recent years. These estrogen - mimicking compounds (xenoestrogens and phytoestrogens) are either man-made or naturally-occurring that enter the environment in many ways and from a variety of sources. Sexual differentiation in teleosts is a process partly regulated by hormones, which makes them sensitive to the action of environmental estrogens. This also makes them useful animal models for the determination of xenoestrogenic effects. Induction of certain processes in the fish system has served as biomarkers of exposure to the said compounds. Among these biomarkers is vitellogenin synthesis in males. Vitellogenin is a female-specific protein yolk precursor that is synthesized in the liver under estrogenic stimulation. The use of zebrafish (Danio rerio) for the assessment of chemicals with possible estrogenic effects has proven to be promising. Sex reversal and gonad development disturbances can be induced in this species after exposure to relatively low concentrations of model substances, which makes it suitable for the evaluation of endocrine disrupting compounds.
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