environmental toxicology and pharmacology 31 ( 2 0 1 1 ) 198–204 available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/etap Differential accumulation levels in the brain of rats exposed to the endocrine disruptor 4-tert-octylphenol (OP) M. Bianco a,b , L. Mita a,c , M. Portaccio a,c , N. Diano a,c , V. Sica a,b , B. De Luca a,c , D.G. Mita a,c,d,∗ , C. Romano Carratelli c , E. Viggiano a,c a National Institute of Biostructures and Biosystems (INBB), Viale Medaglie d’Oro, 305, 00136 Rome, Italy b Department of General Pathology, Second University of Naples, Via L. De Crecchio, 7, 80138 Naples, Italy c Department of Experimental Medicine, Second University of Naples, Via S. M. di Costantinopoli, 16, 80138 Naples, Italy d Institute of Genetics and Biophysics “ABT” of CNR, Via P. Castellino, 111, 80131 Naples, Italy article info Article history: Received 3 May 2010 Received in revised form 29 September 2010 Accepted 28 October 2010 Available online 5 November 2010 Keywords: Endocrine disruptors Brain 4-tert-Octylphenol Environmental pollution abstract Octylphenol (OP) is an endocrine-disrupting chemical that accumulates in various organs. It has also been shown to exert noxious effects on the central nervous system. In the present study, we measured in Sprague–Dawley rats the degree of OP accumulation in different areas of the brain and investigated the effect of OP in pain modulation. Two groups of male Sprague–Dawley rats were treated for 20 days with 50mg/kg BW/day of OP (group 1) or vehicle (group 2). At the end of the treatment, the formalin test was per- formed to evaluate the effect of OP exposure on pain. Soon after, rats were sacrificed, and the accumulation of OP in the cerebral cortex, hippocampus, hypothalamus, cerebellum, thalamus, striatum, mesencephalus and ventral hindbrain was measured by HPLC analy- sis. The results showed a greater accumulation of OP in the cerebral cortex compared to all the other areas; there was also more accumulation in the cerebellum compared to the mesencephalus and thalamus. No accumulation was found in the striatum. These results suggest that there is a preferential accumulation of OP in different areas of the brain with consequences to neural behaviour. On the contrary, experiments on facial grooming did not show significant effects of OP on pain. © 2010 Elsevier B.V. All rights reserved. 1. Introduction It is well known that many environmental chemicals derived from industrial products exert oestrogen-like activity. For this reason, they are called “Endocrine Disruptors” (EDs). In par- ticular, foetuses and neonates are highly sensitive to these physiologically active agents (Warita et al., 2008). EDs are transferred from the mother to the offspring through the pla- centa and via lactation, respectively (Kobayashi et al., 2002). ∗ Corresponding author at: Institute of Genetic and Biophysics of CNR, Via P. Castellino, 111, 80131 Naples, Italy. Tel.: +39 081 6132608; fax: +39 081 6132608. E-mail address: mita@igb.cnr.it (D.G. Mita). Prenatal and neonatal exposure to EDs can disturb develop- ment even though the exposure levels are lower than the no-observed-adverse-effect level (NOAEL) or lower than the lowest-observed-adverse-effect level (LOAEL), as determined by toxicological tests on adult animals (Ceccarelli et al., 2007; Palanza et al., 2008). In this paper, we focus on octylphenol (OP), which shown to compete with 17-beta-estradiol from receptors promoting cell proliferation of oestrogen-dependent cells (White et al., 1994). OP is able to stimulate these biological responses to the same 1382-6689/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.etap.2010.10.008