The effect of the aromatase inhibitor fadrozole and two polynuclear aromatic hydrocarbons on sex steroid secretion by ovarian follicles of coho salmon

A variety of endogenous and exogenous factors can influence sex steroid production by salmon ovarian follicles and ultimately impact reproductive development. We examined the effect of an aromatase inhibitor, fadrozole, and common environmental contaminants (FAHs) on sex steroid secretion by ovarian follicles. Ovarian follicles of coho salmon were incubated in vitro with various concentrations of testosterone (0.10-0.40 mu M) and fadrozole (10 and 100 mu M), or with varying doses (between 0.05 and 5.0 mu M) of the PAHs beta-naphthoflavone (BNF) and 20-methylcholanthrene (20-MC), 17 beta-Estradiol secretion was significantly reduced when follicles were incubated in the presence of fadrozole, BNF, or 20-MC. In contrast, 17 beta-estradial production by ovarian follicles increased in a dose-dependent manner when incubated with increasing doses of the aromatizable able androgen testosterone. Although increasing doses of PAHs significantly reduced follicular 17 beta-estradiol production no effect on testosterone secretion was observed. Hence, both fadrozole and PAHs can significantly reduce 17 beta-estradiol secretion by salmon ovarian follicles and may affect female sexual development. (C) 1997 Academic Press.