Vitellogenin Induction and Increased Plasma 17b-Estradiol Concentrations in Male Nile Tilapia, Oreochromis niloticus, Exposed to Organochlorine Pollutants and Polycyclic Aromatics Hydrocarbons Juan Pablo Rodas-Ortı ´z Æ Victor Ceja-Moreno Æ Maria Eulalia Chan-Cocom Æ Gerardo Gold-Bouchot Received: 5 September 2007 / Accepted: 1 September 2008 / Published online: 12 September 2008 Ó Springer Science+Business Media, LLC 2008 Abstract Vitellogenin (Vtg), 17b-estradiol (E2) and tes- tosterone (T) were used as biomarkers of endocrine disruption in mature male nile tilapia (Oreochromis nil- oticus) from three lakes (Rio, Enmedio and Limon) in Chiapas, Mexico. Vitellogenesis induction was found in tilapias from Rio and Limon, moderately high E 2 levels in Rio and Limon tilapias, compared with controls (cul- tured tilapias). Significant correlations between benzo(a)pyrene (BaP) metabolites and hexachlorobenzene (HCB) with Vtg and E 2 were found. The results of this study indicate that endocrine disruption exists in tilapias from Rio and Limon lakes, and that exposure to HCB and BaP could be causing these alterations. Keywords Vitellogenin Á Estradiol Á Hexachlorobenzene Á Benzo(a)pyrene Á Endocrine disruption Á Tilapia Recently a group of compounds that can cause adverse effects in humans and wildlife have received much atten- tion, the endocrine disruptors (EDs), which are a structurally diverse group of compounds that Kavlock et al. (1996) define as ‘‘exogenous agents that interfere with production, release, transport, metabolism, binding, action or elimination of the natural hormones’’. They include synthetic and natural compounds. Compounds commercially manufactured as organochlorine pesticides (Dichlorodiphenyltrichloroethane (DDT), Chlordecone, Endosulfan, Chlordane and Lindane), industrial products (Polychlorinated biphenyls (PCBs) and phthalates), metals (cadmium, tin, lead and mercury) and pharmaceuticals (ethinylestradiol contraceptive pills), or are produced as a byproduct or degradation product, for example alkyl phe- nols, can be classified as synthetic EDs (Colborn et al. 1993). Natural EDs are synthesized by animals or plants, i.e. natural estrogens (17b-estradiol (E2), estrone and estriol synthesized in mature females) and the phytoes- trogens (isoflavones, lignans and coumestans synthesized by plants and fungi) that can be found in some aquatic environments. The xenoestrogens are the most studied, they are syn- thetic compounds that can mimic natural estrogens causing adverse effects in the development, sexual maturation and reproduction processes (Kavlock et al. 1996). Multiple adverse effects due to exposure to xenoestrogens have been reported, Ankley et al. (1998) in their overview mention effects such as bird eggshell changes, embryo mortality, and reduced fertility, in fish feminization (vitellogenin induction and oocytes presence in testis), delayed sexual maturation, reduced gonadal growth, and altered steroido- genic capacity. Moreover, many adverse effects, for example hormone-dependent cancer (breast, prostate, ovaries and testicles), cryptorchidism (condition in which the testes do not descend into the scrotum) and hypospadias (displacement of urethral opening from the tip to the ven- tral side of the penis) in humans exposed to environmental estrogens have been reported (Rivas et al. 2004). Vitellogenin (Vtg) is a sensitive and powerful biomarker of effect to estrogen receptor (ER) agonists in oviparous vertebrates (Ankley et al. 1998). This lipoprotein is the precursor of the egg yolk proteins phosvitin and lipovitellin, and it is normally present in mature female fish. In male fish the Vtg production is an abnormal process, since male fish J. P. Rodas-Ortı ´z Á V. Ceja-Moreno Á M. E. Chan-Cocom Á G. Gold-Bouchot (&) CINVESTAV Unidad Me ´rida, Km. 6 Antigua Carretera a Progreso, Me ´rida, Yucata ´n CP 97310, Me ´xico e-mail: gerardo.gold@gmail.com 123 Bull Environ Contam Toxicol (2008) 81:543–547 DOI 10.1007/s00128-008-9556-9