Differential accumulation of HCBz and PeCBz in porcine ovarian follicles and their opposing actions on steroid secretion and CYP11, CYP17, 17β-HSD and CYP19 protein expression. A tissue culture approach.

In the current study, we determined in vitro accumulation of hexachlorobenzene (HCBz) and pentachlorobenzene (PeCBz) in porcine ovarian follicles, the effect on steroidogenesis and the expression of enzymes responsible for steroid synthesis. Sixty percent of the HCBz and almost 100% of the PeCBz that was added to the culture medium accumulated in ovarian tissue, and only 1% of each was found in the medium. An inhibitory HCBz effect and stimulatory PeCBz effect on testosterone and estradiol secretion were noted. Immunoblot analyses showed an inhibitory effect of HCBz on CYP17, 17β-HSD and CYP19, a stimulatory effect of PeCBz on CYP17 and CYP19 and no effect on 17β-HSD protein expression. In conclusion, the greater exposure to an estrogenic action of PeCBz than anti-estrogenic HCBz would be a consequence of the preferential accumulation of PeCBz in the ovarian follicles. As one of the mechanisms of action, we propose modulation of steroidogenic enzymes expression.