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INTERLABORATORY STUDY ON THE USE OF STEROID HORMONES IN EXAMINING ENDOCRINE DISRUPTION.
Citation:
McMaster, M. E., J. J. Jardine, G Ankley, W H. Benson, W. J. Greeley, T. S. Gross, L. Guillette Jr., D. MacLatchy, E. Orlando, G. Van Der Kraak, AND Munkittrick. INTERLABORATORY STUDY ON THE USE OF STEROID HORMONES IN EXAMINING ENDOCRINE DISRUPTION. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 20(9):2081-2087, (2001).
Description:
In recent years, there has been an increased use of the measurement of sex steroid hormone levels in the blood of animals exposed to chemicals as an indicator of reproductive impairment or an alteration in endocrine function. Although levels of hormones are often compared among animals and laboratories, there has been no study to examine the among-laboratory variability in actual steroid measurements. White sucker were collected from a site receiving pulp mill effluent, previously documented as having reduced steroid levels. Similar samples were also collected from a reference location. Samples of blood and media from in vitro gonadal incubations were delivered to eight outside laboratories with the ability to measure steroid hormone levels. These laboratories ranged from well-established fish endocrine laboratories to wildlife toxicology laboratories, which recently developed these methods to measure steroid hormones. In this study we have considered both the absolute measure of steroid content between laboratories as well as the ability to discriminate between reference and exposed populations as important criteria when evaluating the utility of these measures. Of the eight outside laboratories conducting the analysis, six detected identical site differences in circulating levels of testosterone and 17b-estradiol as those documented by our Burlington laboratory. However, the absolute value of the steroid hormones measured in the plasma varied significantly (plasma testosterone 0.6-23.1 ng/mL, 17b-estradiol 77.6-1782.7 pg/mL) with Coefficients of Variation of 70.4% and 60.3% respectively. Similar results were demonstrated for the measurement of steroid hormones in media following in vitrogonadal incubation. Although there was a fair amount of variability in the absolute measure of steroid hormone levels, we would predict a far greater coherence of interlaboratory results through the sharing of reagents and the use of a common methodology between laboratories. These results are very promising, providing evidence for the inclusion of steroid hormones in monitoring endocrine disruption in wildlife species.