ABSTRACT
The effects of environmental contaminants on the endocrine system have received increased attention over the past several years. Much of this attention has stemmed from studies on fish and reptiles, which have demonstrated that organic compounds, and particularly organochlorinated compounds, can interact with the estrogen receptor to induce the production of yolk proteins in oviparous males and cause feminization of masculine traits. Although studies in mammals, particularly with rodents, have also shown that certain toxicants can interact with hormone receptors to mimic or inhibit hormone action, the concentrations of exogenous xenobiotics necessary to cause such an effect in adults are very high and this has cast doubt regarding the likelihood that these compounds actually represent a threat to mammalian species. Unlike other mammals, marine mammals represent a unique situation in that their large fat content can act as a pool for trapping contaminants (Colborn and Smolen, 1996). As such, these animals may be exposed to very high concentrations of environmental contaminants from the time of conception via exposure in utero, during breast feeding via the mother’s milk, as well as through accumulation from the food chain during adolescence to adulthood.
