Congener-specific action of PBDEs on steroid secretion, CYP17, 17β-HSD and CYP19 activity and protein expression in porcine ovarian follicles
2011
Karpeta, A. | Rak-Mardyła, A. | Jerzak, J. | Gregoraszczuk, E.L.
The available data on reproductive toxicity of PBDEs are limited. In the present study we evaluated the direct effects of BDE-47, -99 and -100 on porcine ovarian follicular steroid secretions and the activity and expression of enzymes involved in its synthesis. Follicles were exposed to BDE-47 (0.5, 25 and 50ng/ml), BDE-99 (0.25, 10 and 17.5ng/ml), or BDE-100 (0.1, 4 and 12.5ng/ml) for 24h. Progesterone (P4), androstenedione (A4), testosterone (T) and estradiol (E2) levels in the media were determined by EIA. CYP17, 17β-hydroxysteroid dehydrogenase (17β-HSD) and CYP19 activity was measured by conversion of P4>A4, A4>T and T to E2, respectively. Protein expression of CYP17, 17β-HSD and CYP19 was measured by western blot. All of the congeners explored in this study increase testosterone secretion. However, in the case of BDE-47 due to activation of 17 β-HSD and BDE-100 due to activation of CYP17, a corresponding failure to activate CYP19 expression and inhibition of CYP19 activity was seen. The lack of an effect of BDE-99 on the expression and activity of all of the investigated enzymes indicates action on enzymes before progesterone secretion, i.e., STAR or 3β-HSD activity.
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