A Variety of Environmentally Persistent Chemicals, Including Some Phthalate Plasticizers, Are Weakly Estrogenic
Susan Jobling,1 Tracey Reynolds,1 Roger White,2 Malcolm G. Parker,2 and John P. Sumpter1 1Department of Biology and Biochemistry, Brunel University, Uxbridge, Middlesex, UB8 3PH UK
2Laboratory of Molecular Endocrinology, Imperial Cancer Research Fund, London, WC2A 3PX UK Abstract Sewage, a complex mixture of organic and inorganic chemicals, is considered to be a major source of environmental pollution. A random screen of 20 organic man-made chemicals present in liquid effluents revealed that half appeared able to interact with the estradiol receptor. This was demonstrated by their ability to inhibit binding of 17ß-estradiol to the fish estrogen receptor. Further studies, using mammalian estrogen screens in vitro, revealed that the two phthalate esters butylbenzyl phthalate (BBP) and di-n-butylphthalate (DBP) and a food antioxidant, butylated hydroxyanisole (BHA) were estrogenic ; however, they were all less estrogenic than the environmental estrogen octylphenol. Phthalate esters, used in the production of various plastics (including PVC) , are among the most common industrial chemicals. Their ubiquity in the environment and tendency to bioconcentrate in animal fat are well known. Neither BBP nor DBP were able to act as antagonists, indicating that, in the presence of endogenous estrogens, their overall effect would be cumulative. Recently, it has been suggested that environmental estrogens may be etiological agents in several human diseases, including disorders of the male reproductive tract and breast and testicular cancers. The current finding that some phthalate compounds and some food additives are weakly estrogenic in vitro, needs to be supported by further studies on their effects in vivo before any conclusions can be made regarding their possible role in the development of these conditions. Key words: butylbenzyl phthalate, butylated hydroxyanisole, di-n-butylphthalate, phthalates, estrogenicity, sewage. Environ Health Perspect 103: 582-587 (1995) Address correspondence to S. Jobling, Department of Biology and Biochemistry, Brunel University, Uxbridge, Middlesex, UB8 3PH UK. A portion of this work was financially supported by the Department of the Environment, UK. Received 23 March 1995 ; accepted 5 December 1994. The full version of this article is available for free in HTML format. |