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Effects of a Short-term Exposure to the Fungicide Prochloraz on Endocrine Function and Gene Expression in Female Fathead Minnows (Pimephales promelas)
Citation:
SKOLNESS, S. Y., E. J. DURHAN, N. GARCIA-REYERO, K. M. JENSEN, M. D. KAHL, E. A. MAKYNEN, D. MARTINOVIC-WEIGELT, E. PERKINS, DAN VILLENEUVE, AND G. T. ANKLEY. Effects of a Short-term Exposure to the Fungicide Prochloraz on Endocrine Function and Gene Expression in Female Fathead Minnows (Pimephales promelas) . AQUATIC TOXICOLOGY. Elsevier Science Ltd, New York, NY, 103(3-4):170-178, (2011).
Impact/Purpose:
To document research results.
Description:
Prochloraz is a fungicide known to cause endocrine disruption through effects on the hypothalamic-pituitary-gonadal (HPG) axis. To determine the short-term impacts of prochloraz on gene expression and steroid production, adult female fathead minnows (Pimephales promelas) were exposed to the chemical (0 or 200 ìg/L) for a time-course of 6, 12 and 24 hours. Consistent with inhibition of cytochrome P450 17á-hydroxylase/17,20-lyase (CYP17) and aromatase (CYP19), known molecular targets of prochloraz, plasma 17â-estradiol (E2) was reduced within 6 hours. Ex vivo E2 production was significantly reduced at all time points, while ex vivo testosterone (T) production remained unchanged. Consistent with the decrease in E2 levels, plasma concentrations of the estrogen-responsive protein vitellogenin were significantly reduced at 24 hours. Genes coding for CYP19, a key enzyme that converts T to E2, CYP17, and steroidogenic acute regulatory protein were up-regulated in a compensatory manner in the ovaries of the prochloraz-treated fish. In addition to targeted quantitative real-time polymerase chain reaction analyses, a 15k feature fathead minnow microarray was used to determine gene expression profiles in ovaries. From time-point to time-point, the microarray results showed a relatively rapid change in the differentially expressed gene (DEG) profiles associated with the chemical exposure. Functional analysis of the DEGs indicated changes in expression of genes associated with cofactor and coenzyme binding (GO: 0048037 and 0050662), fatty acid binding (GO:0005504) and organelle organization and biogenesis (GO: 0006996). Overall, the results from this study are consistent with compensation of the fish HPG axis to inhibition of steroidogenesis by prochloraz, and provide further insights into relatively rapid, system-wide, effects of a model chemical stressor on fish.