ABSTRACT
Endocrine-disrupting chemicals (EDCs) are environmental contaminants, persistent and capable of interfering with endocrine system functions (Sumpter 1998). A major group of EDCs are called xenoestrogens since they exert estrogenic effects on the human body, including interference with reproductive, neurologic, and immunologic functions, and even carcinogenesis (Nilsson et al. 2001). Some of these xenocompounds have a structure similar to estrogens and hence exhibit an affi nity for the human estrogen receptors (ERs). The strong similarity between xenoestrogens and estrogens is the main reason for the increase of some diseases, among which it is possible to identify infertility, functional alterations of sexual development and some types of cancer (Mueller 2004). The xenoestrogens list includes some phenolic compounds and, among these, Catechol and Bisphenol A (BPA). Bisphenol A (2,2-bis(4-hydroxyphenyl)propane), is a chemical substance widely employed as a monomer in the production of epoxy resins and polycarbonates, and as an antioxidant in PVC plastics. Epoxy resins are used as coating of inner surfaces of cans containing food and beverages. Polycarbonates are used in the manufacture of plastic containers for food, such as infant feeding bottles and tableware. PVC is also used in a variety of products which come in contact with food, such as cling fi lm used for food packaging. The migration of BPA from epoxy-coated surfaces, polycarbonate plastics and PVC products into food simulants or food has been reported (Lopez-Cervantes and Paseiro-Losada 2003; Nerin et al. 2003; Goodson et al. 2004). In addition, it has been reported that BPA exhibits estrogenic activity in in vitro assays at concentrations of 10-25 nM (2-5 ng/mL), competing with estradiol for binding to estrogen receptors (Krishnan et al. 1993). Moreover, using oral administration, studies in vitro on mice (vom Saal et al. 1998) have shown that a BPA dose of 2 ng/g of
body weight affected the size of reproductive organs of male offspring fed by this substance during pregnancy, and a dose of BPA 20 ng/g of body weight signifi cantly decreased effi ciency of sperm production by 20% relative to control males.
