Aromatase and endocrine disruptors
There is growing evidence that some environmental
contaminants, considered as endocrine disruptors
(EDCs) have the ability to modulate and/or disrupt
the endocrine system in vertebrates (Colborn et al.
1993). Among the possible biomarkers used to test
the effects of EDCs, particularly xenoestrogens,
vitellogenin production and CYP1A gene expression
are the most widely assessed. More recently, the
ability of several xenoestrogens to change aromatase
gene expression and enzymatic activity has been
demonstrated. In this regard, estrogenic compounds
and synthetic estrogens have been shown to strongly
up-regulate cyp19b gene expression in the zebrafish
whereas all but a synthetic estrogen failed to induce
any change in cyp19a gene expression (Kazeto et al.
2004). Enhancement of transcription of cyp19b after
estrogen treatment has been shown in several fish
species including tilapia (Tsai et al. 2000), black
porgy (Lee et al. 2000), goldfish (Callard et al. 2001),
and zebrafish (Kazeto et al. 2004). The fact that