Halowax 1051 affects steroidogenesis, 17β-hydroxysteroid dehydrogenase (17β-HSD) and cytochrome P450arom (CYP19) activity, and protein expression in porcine ovarian follicles

We evaluated the effect of Halowax 1051 on ovarian follicular testosterone (T) and estradiol (E2) secretion determined by EIA and on the expression of 17β-HSD and CYP19 analyzed by Western blot. 17β-HSD and CYP19 activity were determined indirectly by measuring the conversion of androstenedione (A4) to T and T to E2, respectively. Additionally, CYP19 activity by dibenzylfluorescein assay. Follicles were exposed to 1–1000 pg/ml of Halowax 1051 for 24, 48 or 72 h. It was found that Halowax 1051, in all doses used, increased basal T secretion concomitant with a decrease in basal E2 secretion. Inhibitory action on 17β-HSD and stimulatory action on CYP19 (activity and protein expression) under the influence of 1 pg/ml, and opposite effect under the influence of 10–1000 pg/ml was noted. In conclusion, we suggest non-linear dose–response effect of Halowax 1051 on steroidogenesis and steroidogenic enzymes activity and protein expression.

► Non-linear dose–response effect of Halowax 1051 on ovarian steroidogenesis.
► Inhibitory action of small doses on 17β-HSD and stimulatory action on CYP19 activity.
► Opposite effect of higher doses.