Gender benders at the beach: Endocrine disruption in marine and estuarine organisms

Several consensus definitions of the term endocrine disrupter have appeared recently, but all definitions include the important, though frequently imp licit, stipulation that the animal is not distressed or in obvious discomfo rt. Instead, a superficially healthy animal is experiencing alterations in hormone synthesis, transport, receptor interaction, metabolism, excretion, or feedback regulation. In addition, hormone disruption may occur during se x differentiation, and its effects may not be manifested until after sexual maturation. Many cases of chemically induced reproductive impairment have been reported for both freshwater and marine species. However, reproductive impairment may not necessarily result from hormone disruption and should b e considered suggestive, but not conclusive, evidence of endocrine disrupti on. A suite of in vivo and in vitro assays will more adequately assess whet her a compound is truly endocrine disrupting. This review will cover basic endocrinology of marine and estuarine invertebrates and vertebrates, method s for detecting endocrine disruption, and examples of endocrine disruption in various species.