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A SHORT-TERM REPRODUCTIVE TEST WITH THE FATHEAD MINNOW (PIMEPHALES PROMELAS)
Citation:
Ankley, G T., K M. Jensen, M D. Kahl, J J. Korte, AND E A. Makynen. A SHORT-TERM REPRODUCTIVE TEST WITH THE FATHEAD MINNOW (PIMEPHALES PROMELAS). Presented at 21st SETAC Annual Meeting, Nashville, TN, November 12-16, 2000.
Description:
Due to the time and expense associated with full life-cycle testing, most current toxicity tests with fish do not explicity consider reproductive output as an endpoint but, rather, focus on early life-stage survival and development. However, there are classes of chemicals that could adversely affect reproduction at concentrations below those that affect development. Further, estimates of the effects of toxic chemicals on reproductive output are critical to the development of probabilistic risk assessments. This talk will provide an overview of a short-term reproductive test with the fathead minnow (Pimephales promelas), and present data from assays with a series of chemicals expected to impact reproduction through alterations in specific aspects of endocrine function (methoxychlor, methyltestosterone, vinclozolin, flutamide, fadrazole). The assay is conducted with mature animals exposed to test chemicals for <_ 21 d, during which time behavior, secondary sex characteristics, fecundity, fertility and early (F1) development can be determined. At conclusion of the assay, several endpoints specifically associated with endocrine function are assessed, including plasma concentrations of vitellogenin and sex steroids, and gonadal status (relative weight, histopathology). The test is relatively cost-effective, and can be completed in a time frame which is a which is fraction of that required to complete a traditional full liffe-cycle study. Although initial test development focused on endpoints specific to endocrine function, the basic reproductive assay should prove applicable to diverse risk assessment scenarios.