Reproductive Toxicology 32 (2011) 379–384 Contents lists available at SciVerse ScienceDirect Reproductive Toxicology jo u r n al hom epa ge: ww w.elsevier.com/locate/reprotox Halowax 1051 affects steroidogenesis, 17-hydroxysteroid dehydrogenase (17-HSD) and cytochrome P450arom (CYP19) activity, and protein expression in porcine ovarian follicles Ewa Lucja Gregoraszczuk a,∗ , Justyna Jerzak a , Agnieszka Rak-Mardyła a , Jerzy Falandysz b a Department of Physiology and Toxicology of Reproduction, Institute of Zoology, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland b Research Group of Environmental Chemistry, Ecotoxicology & Food Toxicology, Institute of Environmental Sciences & Public Health, University of Gdansk, Sobieskiego 18, 80-952 Gdansk, Poland a r t i c l e i n f o Article history: Received 18 April 2011 Received in revised form 3 September 2011 Accepted 28 September 2011 Available online xxx Keywords: PCNs Ovarian follicles Testosterone Estradiol 17-HSD CYP19 a b s t r a c t We evaluated the effect of Halowax 1051 on ovarian follicular testosterone (T) and estradiol (E2) secretion determined by EIA and on the expression of 17-HSD and CYP19 analyzed by Western blot. 17-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 17-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. © 2011 Elsevier Inc. All rights reserved. 1. Introduction Polychlorinated naphthalenes (PCNs) form a large and diverse group of compounds with several applications in numerous branches of industry [1]. PCNs always occur as mixtures of con- geners sold under various trade names (e.g., Halowax, Nibren Wax, or Seekay Wax) [2]. The lower chlorinated PCN mixtures were used predominantly as lubricants whereas the higher chlorinated mixtures were used for capacitor impregnation and electrical insu- lation. Commercial production of these mixtures ceased in 1980 [1]. However, humans continue to be exposed to PCN contaminants contained in many environmental matrices such as ambient air and vegetation [2–4], meats and fats [5], seafood [6–8] and industrial and commercial goods world-wide [9]. Foods that nowadays fre- quently contain traces of PCNs which are globally contaminants are major source of intake [2]. PCNs are also prevalent contaminants in human body fluids and tissues [2]. In recent study of human serum from Korean’s volunteers the mean PCNs concentration was 2170 pg/g lipid and these compounds contributed highly to the overall dioxin-like toxicity in those sera and especially 1,2,3,4,5,6,7- HeptaCN (no. 73) [10]. ∗ Corresponding author. Tel.: +48 12 664 50 02; fax: +48 12 634 37 16. E-mail address: ewa.gregoraszczuk@uj.edu.pl (E.L. Gregoraszczuk). Toxicological properties of PCNs are similar to those caused by polychlorinated biphenyls (PCBs), polychlorodibenzodioxins (PCDDs), and polychlorodibenzofurans (PCDFs) [1,11,12]. Numer- ous studies have shown that the environmental exposure of women to compounds such as 2,3,7,8-TCDD (tetrachlorobibenzodioxin) and PCBs exert adverse effects on fertility, manifested by the increased incidence of miscarriages (significantly increased inci- dence of spontaneous abortions and complications at conception) and a lower birth weight of offspring [13,14]. We have previously shown that both TCDD and PCB congeners 126 and 153 accumu- lated in ovarian follicles and showed adverse effects on ovarian and placental cells steroidogenesis [15–18]. Those results are the reason that the potential toxic effect of PCNs on fertility cannot be ruled out, as they are characterized by a similar mechanism of toxicity. In the existing literature, octa- and hepta-chlorinated naphthalene (CN) homologue groups, which are the main CN constituents of Halowax 1051 with declared 90% and 10% contents, respectively [19] have not been tested for adverse effects on reproduction. To predict the effects of pollu- tants on animal or human reproductive health, it is necessary to adapt physiological models to include target tissues that not only are responsive to estrogenic compounds but that also produce steroids, including estradiol. In certain cases, the complexity of in vivo studies can complicate the interpretation and prediction of substance-induced effects related to reproductive health. 0890-6238/$ – see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.reprotox.2011.09.008