Welcome to the Revolution: Integrative Biology and Assessing the Impact of Endocrine Disruptors on Environmental and Public Health

Abstract

Concern continues to grow over the negative impact of endocrine disrupting chemicals on environmental and public health. The number of identified endocrine disrupting chemicals is increasing, but biological endpoints, experimental design, and approaches for examining and assessing the impact of these chemicals are still debated. Although some workers consider endocrine disruption an "emerging science," I argue here that it is equally, a "merging science" developing in the tradition of integrative biology. Understanding the impact of endocrine disruptors on humans and wildlife is an examination of "context dependent development" and one that Scott Gilbert predicted would require a "new synthesis" or a "revolution" in the biological sciences. Here, I use atrazine as an example to demonstrate the importance of an integrative approach in understanding endocrine disruptors.Atrazine is a potent endocrine disruptor that chemically castrates and feminizes amphibians and other wildlife. These effects are the result of the induction of aromatase, the enzyme that converts androgens to estrogens, and this mechanism has been confirmed in all vertebrate classes examined (fish, amphibians, reptiles, birds, and mammals, including humans). To truly assess the impact of atrazine on amphibians in the wild, diverse fields of study including endocrinology, developmental biology, molecular biology, cellular biology, ecology, and evolutionary biology need to be invoked. To understand fully the long-term impacts on the environment, meteorology, geology, hydrology, chemistry, statistics, mathematics and other disciplines well outside of the biological sciences are required.

Atrazine-Induced Aromatase Expression Is SF-1 Dependent: Implications for Endocrine Disruption in Wildlife and Reproductive Cancers in Humans

“…In fact, the activity of atrazine and simazine at 10 −7 M (21.57 mol/L) in the present study is in the range that chemically castrates and feminizes male amphibians (0.1–20 ppb; 1 ppb = 1 mol/L) (Carr et al 2003; Hayes 2004, 2005; Hayes et al 2002a, 2002b, 2003, 2006a, 2006b; McKoy et al 2002; Miyahara et al, unpublished data; Reeder et al 1998; Tavera-Mendoza et al 2002) and fish (6 ppb) (Moore and Waring 1998). Thus, the present study is also significant because the effects in wildlife likely occur through the same molecular mechanisms as documented here; however, the cell lines and molecular tools are not available for wildlife species to examine these effects on this same level.…”

Prenatal exposure to low doses of atrazine affects mating behaviors in male guppies

“…Atrazine has been postulated to upregulate the production of the enzyme aromatase that is necessary for the conversion of testosterone to estradiol (Fan et al, 2007;Hayes, 2005). This mechanism has been debated (Hecker et al, 2005).…”

“…Depending on the type of crop and application rate, atrazine concentrations in water bodies around agricultural fields are expected to be in the range of 19-194 ppb over a 90 day period (US EPA, 2006). It has been hypothesized that atrazine induces aromatization of testosterone to estradiol (Fan et al, 2007;Hayes, 2005), but this mechanism has been debated (Hecker et al, 2005). Several studies have demonstrated the feminizing effects of atrazine in amphibians (Hayes et al, 2002a(Hayes et al, , 2002b(Hayes et al, , 2003(Hayes et al, , 2010, fish (Shenoy, 2012), and other animal taxa (Rohr and McCoy, 2010).…”

Vertebrate diets derived from trophically transmitted fish parasites in the Bothnian Bay

“…Clearly the most detailed vertebrate subweb was generated by considering both parasites and observed diet together, demonstrating the value of more complete studies based on diVerent types of information (e.g. see Begg and Waldman 1999;Johnson et al 2004;Hayes 2005;Marcogliese, 2008). Indeed, Johnson et al (2004) concluded that observed diet and age-size class separation were insuYcient in the determination of perch food web interactions, and LaVerty et al (2006a) suggest that the most comprehensive webs are those derived from multiple sources of information, including parasitism (see also Baldwin et al 2008).…”