J. Charles Eldridge, PhD
J. Charles Eldridge, PhD - Research
Our lab has been active in a rapidly expanding field of Endocrine Toxicology. We investigate mechanisms by which environmental pollutants, now often called “endocrine disruptors”, can interact with synthesis and actions of hormones. This interest draws on a background in endocrine physiology and pharmacology, and more specifically the hormonal control of reproduction. Through extramural support by government and industry we have been involved in two principal lines of work:
Chlorotriazines, principally atrazine, are a class of herbicides used widely in the agriculture industry. In partnership with a principal manufacturer we investigated mechanisms underlying the premature appearance of mammary tumors in female rats during long-term exposure. We initially determined that the herbicides are not estrogenic (a property that would directly stimulate tumor growth). We then noted irregularities of estrous cycling patterns in treated female rats and determined that atrazine administration diminished pituitary LH surges necessary for regular, cyclic ovulation. Failure to ovulate could lead to an elevated estrogen environment and promotion of mammary tumor growth. Investigations continue on mechanisms underlying this neuroendocrine action of chlorotriazines.
Xenoestrogen Receptor Binding
It is suspected that many hormonally active chemicals contaminate the environment. One group of particular concern are substances that can imitate or inhibit estrogen action. Estrogens principally act on cells via specific receptor proteins, so one way to identify putative estrogen agonists or antagonists is to assess their ability to bind to estrogen receptors in vitro. With support from the US Environmental Protection Agency, we have been investigating binding properties of a number of chemicals identified on the basis of structure.
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