You are here:
Short-term effects of propiconazole on hypothalamic-pituitary-gonadal function in the fathead minnows (Pimephales promelas)
Skolness, S., E. Durhan, K. Jensen, M. Kahl, C. LaLone, L. Makynen, Dan Villeneuve, AND G. Ankley. Short-term effects of propiconazole on hypothalamic-pituitary-gonadal function in the fathead minnows (Pimephales promelas). Presented at Society for Environmental Toxicology and Chemistry.
Propiconazole is an ergosterol inhibitor commonly used in agriculture and has been detected in aquatic environments. Ergosterol inhibitors decrease fungal growth through effects on 14á-demethylase, a cytochrome P450 (CYP), isoform important for ergosterol biosynthesis. In higher organisms, other CYPs are targets for ergosterol inhibiting compounds, such as CYPs involved in sex steroid synthesis or those responsible for Phase I xenobiotic metabolism. To determine the short-term effects of propiconazole on endpoints related to function of the hypothalamic-pituitary-gonadal axis, adult female fathead minnows (Pimephales promelas) were exposed to 0 or 1000 ìg/L of the fungicide via the water. The fish were treated for up to 24 hours, with sampling at 6, 12, and 24 hours when plasma, liver and ovary were collected. Ovarian ex vivo production of testosterone and 17â-estradiol (E2) and plasma E2 were determined by radioimmunoassay. Additionally, quantitative real-time PCR was used to examine expression of a number of genes in ovary and liver. Propiconazole rapidly reduced circulating E2 concentrations and ex vivo E2 production, but had no effect on the ovarian expression of genes coding for proteins related to steroidogenesis, including steroidogenic acute regulatory protein and CYP19 aromatase. Hepatic expression of cyp1a1, which is involved in metabolism of xenobiotics, was significantly up-regulated at all time-points. This study will aid in understanding the short-term responses of the liver-ovary axis to endocrine disrupting chemicals