Peter M. Vonier

Learn More
Certain chemicals in the environment are estrogenic. The low potencies of these compounds, when studied singly, suggest that they may have little effect on biological systems. The estrogenic potencies of combinations of such chemicals were screened in a simple yeast estrogen system (YES) containing human estrogen receptor (hER). Combinations of two weak(More)
The possible contribution of endocrine disrupters to human disease, particularly those compounds that modulate the estrogen receptor (ER), has recently drawn considerable attention. The tissue specificity of effects mediated by the ER is well recognized, although the mechanism of this specificity is not understood sufficiently to predict the effects of a(More)
Reports of reproductive abnormalities in the American alligator from Lake Apopka, Florida, have been linked to a spill of DDT and other pesticides suspected of having hormonelike activity. To determine whether environmental chemicals had the potential to function as exogenous hormones in the American alligator, we examined the ability of chemicals to bind(More)
A protein extract prepared from the egg shell fiber-secreting region of the oviduct of Alligator mississippiensis was assayed for the presence of receptors for estrogen and progesterone. In the presence of [3H]-estradiol-17 beta, the extract contained an estrogen-binding activity which reached equilibrium at 25 degrees C in 1 h. Scatchard analysis(More)
Using a combination of in vitro assays we have evaluated whether DDT metabolites can interact with the progesterone receptor pathway in yeast expressing human progesterone receptor (hPR) and in T47D human breast cancer cells which express endogenous hPR. In transactivation assays using both yeast and T47D cells, o,p'-DDT and the metabolites p,p'-DDT,(More)
Endogenous and exogenous chemical signals have evolved as a means for organisms to respond to physical or biological stimuli in the environment. Sensitivity to these signals can make organisms vulnerable to inadvertent signals from xenobiotics. In this review we discuss how various chemicals can interact with steroid-like signaling pathways, especially(More)
The effect of mixtures of environmental chemicals with hormonal activity has not been well studied. To investigate this phenomenon, the estrogen receptor (ER) from the American alligator (aER) or human (hER) was incubated with [3H]17beta-estradiol in the presence of selected environmental chemicals individually or in combination. The environmental chemicals(More)
Top predators, like the American alligator (Alligator mississippiensis) bioaccumulate and biomagnify persistent pollutants, such as organochlorine pesticides. In a recently published study, several pesticides and pesticide metabolites not previously reported in alligator eggs were identified in the serum of juvenile alligators. This study examines the(More)
The remarkable frequency of uterine leiomyoma in the human population calls into question the potential for the participation of environmental factors in tumor etiology. Having been implicated in the dramatic rise in hormone-related cancers in recent years, endocrine disruptors are salient suspects in this pathogenesis, although the mechanism by which they(More)
Environmental contaminants have been reported to function as hormone mimics in various wildlife species. To investigate a potential mechanism for the interaction of contaminants with the endocrine system, we evaluated the cellular bioavailability of numerous chemicals. Hormone binding proteins from oviductal cytosol of the American alligator (Alligator(More)