Love Song Blues: DEHP Alters Courtship Vocalizations in Mice

Due to its prevalence and known endocrine-disrupting properties, DEHP [di(2-ethylhexyl) phthalate] has been subject to extensive research into potential human health effects, especially related to the reproductive system.34 An article in Environmental Health Perspectives reports evidence that even small doses of DEHP may alter the courtship behavior of otherwise healthy adult male mice by reducing the number of androgen receptors in the brain. These receptors perform vital functions related to reproduction and sexuality. Phthalates, including DEHP, are widespread in modern life. About a dozen variants are commonly used worldwide to make the plastics in consumer products, packaging, and medical devices more flexible or durable. DEHP, by far the most common of these, represents more than a third of the global plasticizer market and has been detected in more than 75% of analyzed individuals in industrial countries. Over the years, experimental and epidemiological studies have implicated DEHP in a range of health effects, leading some countries, including the United States, to ban or limit its use in certain applications.141516 Less is known about the chemical’s potential effects on the brain, but recent research has suggested associations between developmental exposure to DEHP and impaired neurodevelopment,1718 behavioral problems, anxiety and depression, and altered stress responses. In this new experimental study, researchers from France’s National Center for Scientific Research fed healthy adult mice 0.5, 5, or 50 lg=kg=day DEHP. The highest dose corresponds to the tolerable daily intake for humans established by the European Food Safety Authority, while the lower two are in the range of global exposure levels documented in previous studies. After a period of 4 weeks, the researchers performed a series of tests to assess reproductive behavior in the DEHP-dosed mice and nonexposed controls. They found all three doses to be associated with altered courtship vocalizations—key to the reproductive behavior of not only mice, but also many fish, amphibian, bird, and mammal species. The two higher doses of 50 and 5 lg=kg=day also were associated with delayed initiation of mating by the male mice.