2 research outputs found
Re-evaluating the Significance of Estrone as an Environmental Estrogen
Studies
worldwide have demonstrated the occurrence of feminized
male fish at sites impacted by human and animal wastes. A variety
of chemicals could contribute to this phenomenon, but those receiving
the greatest attention in terms of research and monitoring have been
17β-estradiol (β-E2) and 17α-ethinylestradiol, due
both to their prevalence in the environment and strong estrogenic
potency. A third steroid, estrone (E1), also can occur at high concentrations
in surface waters but generally has been of lesser concern due to
its relatively lower affinity for vertebrate estrogen receptors. In
an initial experiment, male fathead minnow (<i>Pimephales promelas</i>) adults were exposed for 4-d to environmentally relevant levels
of waterborne E1, which resulted in plasma β-E2 concentrations
similar to those found in reproductively active females. In a second
exposure we used <sup>13</sup>C-labeled E1, together with liquid chromatography-tandem
mass spectrometry, to demonstrate that elevated β-E2 measured
in the plasma of the male fish was indeed derived from the external
environment, most likely via a conversion catalyzed by one or more
17β-hydroxysteroid dehydrogenases. The results of our studies
suggest that the potential impact of E1 as an environmental estrogen
currently is underestimated
Re-evaluating the Significance of Estrone as an Environmental Estrogen
Studies
worldwide have demonstrated the occurrence of feminized
male fish at sites impacted by human and animal wastes. A variety
of chemicals could contribute to this phenomenon, but those receiving
the greatest attention in terms of research and monitoring have been
17β-estradiol (β-E2) and 17α-ethinylestradiol, due
both to their prevalence in the environment and strong estrogenic
potency. A third steroid, estrone (E1), also can occur at high concentrations
in surface waters but generally has been of lesser concern due to
its relatively lower affinity for vertebrate estrogen receptors. In
an initial experiment, male fathead minnow (<i>Pimephales promelas</i>) adults were exposed for 4-d to environmentally relevant levels
of waterborne E1, which resulted in plasma β-E2 concentrations
similar to those found in reproductively active females. In a second
exposure we used <sup>13</sup>C-labeled E1, together with liquid chromatography-tandem
mass spectrometry, to demonstrate that elevated β-E2 measured
in the plasma of the male fish was indeed derived from the external
environment, most likely via a conversion catalyzed by one or more
17β-hydroxysteroid dehydrogenases. The results of our studies
suggest that the potential impact of E1 as an environmental estrogen
currently is underestimated