Endocrine-Disrupting Agents on Healthy Human Tissues

A vast number of substances have been suggested as possibly contributing to perturbation of the endocrine system. Several have been tested with different approaches ranging from yeast expression system of human oestrogenic receptors to human breast cancer cells assays. Surprisingly, no inhibition-binding experiments to steroid receptors on healthy human tissue have been performed so far. Our study provides inhibition binding experiments to oestrogens, progesterone, testosterone and retinoic acid receptors in prostate and uterine human tissue of organochlorine pesticides, phthalate esters, oestrogenic constituents derived from plants and phenol derivates. Affinities of significant extent of phthalates on oestrogenic, progestinic and androgenic receptors have not been detected. As for retinoic acid receptors, mono(2-ethylexyl)phthalate provokes a notable reduction of the binding of the tritiated retinoic acid, phtalic acid ethyl- n-butyl ester and 4-octylphenol show an affinity comparable to that of isoflavonoid genistein, whereas 4-nonylphenol reduces the binding of retinoic acid in prostate. The possibility of wide-spread adverse human and wild-life impacts from environmental chemicals causing interference with normal endocrine function has received increasing attention from the scientific community, the media, and other parties concerned over the last several years. Several studies deal with this matter. The incidence of female breast cancer has increased substantially since 1950. A frequently cited article in 1993 suggested a connection between breast cancer and man-made oestrogen-like chemicals (Davis et al. 1993). The effects most often cited as possibly due to indus- trial ''endocrine disruptors'' are declining sperm counts, dramatic increases in prostate and testicular cancer, and in- crease in the incidence of cryptorchidism, and abnormalities in the reproductive organ (McLeod & Wang 1979). Most frequently cited are sex differentiation and reproductive problems in fish-eating birds, feminization of trout and re- productive abnormalities and failures among alligators in Florida's Lake Apopka (Rolland et al. 1995). In the last few years the basic hypothesis has been intro- duced that a wide variety of man-made chemicals in com- monly used throughout the world, and particularly the ones that persist and accumulate in the environment and human and wild-life tissues, may be interfering with the normal functioning of human and wild-life endocrine systems thus causing the above mentioned effects. Recently new studies have given rise to an international debate which has brought the terms of the problems into focus. Arnold et al. (1996) have found 150 to 1600 times