Evidence of endocrine alteration in the red mullet, Mullus barbatus from the NW Mediterranean Rebeca Martin-Skilton a , Ramo ´n Lavado a , Re ´mi Thibaut a , Christophe Minier b , Cinta Porte a, * a Department of Environmental Chemistry, IIQAB-CSIC, Jordi Girona 18, 08034 Barcelona, Spain b Laboratoire d’E ´ cotoxicologie, Universite ´ du Havre, 25 rue Philippe Lebon, B.P. 540, F-76058 Le Havre, France Received 8 February 2005; accepted 5 August 2005 Red mullet may be more susceptible to endocrine disruptors during the reproductive period. Abstract Red mullet (Mullus barbatus) were collected from different sampling sites (NW Mediterranean) in spring and autumn, with the aim of assessing potential alterations of the endocrine system. Alkylphenols were measured in fish bile as an indicator of estrogenic exposure. Key enzymatic activities involved in both synthesis (ovarian 17b-hydroxysteroid dehydrogenases and P450 aromatase) and metabolism of steroids were assessed together with histological alterations of the gonads. During the spring sampling, delayed gamete maturation, intersexuality, fibrosis, and depressed ovarian P450 aromatase activity were observed in organisms from the most polluted sites. During the autumn sampling, those effects were less evident, indicating that fish might be more susceptible to endocrine disrupting chemicals during the reproductive period. Nonetheless, enhanced glucuronidation of testosterone and estradiol was observed. Overall, this work provides first evidences of significant alterations in the endocrine system of red mullet from highly impacted areas in the NW Mediterranean. Ó 2005 Elsevier Ltd. All rights reserved. Keywords: Mullus barbatus; Alkylphenols; Uridine diphosphate-glucuronosyltransferase; Ovarian P-450 aromatase; 17b-Hydroxysteroid dehydrogenase; Intersex 1. Introduction The NW Mediterranean Sea is the recipient of extensive urban and industrial wastewater discharges from bordering countries, through continental runoff, sewage sludge disposal, and atmospheric deposition. Fish inhabiting coastal areas have often been used as sentinel organisms for monitoring land- based pollution as they may concentrate indicative hydropho- bic compounds in their tissues (Porte and Albaige ´s, 1993). More recently, biomonitoring programs have integrated the analyses of xenobiotics together with biochemical and cellular responses in coastal fish in order to assess both fate of pollutants and impact (Burgeot et al., 1996; Porte et al., 2002, Regoli et al., 2002). However, information on the effect of those pollutants in the endocrine system of coastal fish is rarely available, particularly in the Mediterranean area. A recent work has indicated induction of vitelogenin and zona radiata proteins in adult male specimens of three species of pelagic fish predators (bluefin tuna, swordfish and the Mediterranean spearfish), and this has been attributed to high exposure to organohalogenated chemicals (Fossi et al., 2002). The presence of intersexuality in a wild population of Mediterranean swordfish has also been reported (De Metrio et al., 2003). The red mullet, Mullus barbatus, a benthic and territorial fish of commercial interest in the region, has been used for many years in coastal pollution monitoring programs (Porte * Corresponding author. Tel.: C34 9 3400 6175; fax: C34 9 3204 5904. E-mail address: cpvqam@cid.csic.es (C. Porte). 0269-7491/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.envpol.2005.08.016 Environmental Pollution 141 (2006) 60e68 www.elsevier.com/locate/envpol