Induction of zona radiata and vitellogenin genes in estradiol and nonylphenol exposed male sheepshead minnows (Cyprinodon variegatus)

Several genes normally induced by estradiol (E-2) in female fish, those for vitellogenins (VTGs) and zona radiata proteins (ZRPs), are also inducible in males exposed to estrogenic chemicals. Male sheepshead minnows (SHM) were exposed to both E-2 and para-nonylphenol (NP), at several doses and times to determine a dose-response. Quantitative real time PCR was used to measure mRNA for VTG1, VTG2, ZRP2 and ZRP3. Both E-2 and NP elicited a dose-response increase in all of the mRNAs tested. Exposure to both chemicals resulted in VTG2 expression at about a 10-fold lower level than VTG1, and ZRP2 expression at a lower level than ZRP3. (C) 2004 Elsevier Ltd. All rights reserved.