Research

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We study susceptibility to environmental disease through integrated studies of people, rodents, and cells. We are currently investigating:

  • Perinatal exposures and risk of metabolic syndrome
  • Perinatal exposures and risk of breast cancer
  • Gene regulation in thermogenesis

Perinatal exposures and risk of metabolic syndrome

The metabolic syndrome describes the clustered occurrence of at least three of the following findings: increased blood pressure, adiposity, fasting glucose, cholesterol, and triglyceride levels. We are currently evaluating whether perinatal exposure to DDT and DDE increases risk of metabolic syndrome in both people and mice. Learn more about our mouse study of DDT and metabolic syndrome in the LA Times or the London Telegraph. We are currently studying the Child Health and Development Studies cohort to help us address this question in people. Our collaboration with OEHHA seeks to develop a risk assessment based on scientific literature and our experimental screens for environmental chemicals that disrupt insulin action. To learn more about this field, listen to Dr. La Merrill’s podcast with the journal Environmental Health Perspectives about the interaction of persistent organic pollutants and adipose tissue.

Perinatal exposures and risk of breast cancer

The discovery that diethylstilbesterol exposure in utero causes cancer of reproductive organs in women raises the possibility that other man-made chemicals, particularly those that disrupt normal estrogen-related functions, could cause breast cancer in later life. We previously demonstrated that prenatal exposure to dioxin combined with a high fat diet to increase mammary tumors in adult mice. This appeared to result from enhanced genotoxic metabolism of estrogen combined with prolonged pubertal mammary tree expansion. We have recently shown that perinatal exposure to DDT is associated with increased risk of breast cancer in adult women. We are currently investigating the mechanism of these DDT effects using translational research approaches. Learn more about our human study of DDT exposure in utero and breast cancer by reading the National Geographic or listening to NBC Nightly News.

Gene regulation in thermogenesis

Proper maintenance of thermogenesis is essential to mammalian life. We have found that perinatal DDT exposure impairs thermogenesis in mice. This was a major contributor to decreased energy expenditure in mice exposed to DDT perinatally. Perinatal DDT exposure also increased susceptibility to obesity and to diet-induced insulin resistance. DDT-induced changes in thermogenesis seen in brown adipose tissue of adult mice appeared to be mediated by long term molecular signaling changes rather than pathological changes. To learn more about this research, listen to Dr. La Merrill's 20 minute presentation to the Collaborative on Health and the Environment, or her 40 minute presentation to Chico State University. We are currently studying the developmental origins of the regulation of these transcriptional changes.