Effects of 4-nonlyphenol on vitellogenesis response: in vivo studies of interspecies differences

Abstract

Three kinds of juvenile marine fish (Paralichthys olivaceus, Sebastes schlegeli, Pagrus major) were exposed continuously to aqueous measured concentration of 10 ug 4-nonylphenol (4-NP) per L, 50 and 100 ug 4-NP per L for 7 days using an intermittent flow-through dosing apparatus. Plasma vitellogenin (VTG) and hepatic VTG mRNA were determined in a group of fish sampled during exposure phase. In two fish species (Paralichthys olivaceus and Sebastes schlegeli) increased VTG mRNA was apparent in four day of exposure. VTG protein level in Paralichthys olivaceus and Pagrus major was induced at 50 ug 4-NP per L from fourth day of exposure and Sebastes schlegeli was induced at 20 ug 4-NP per L. Plasma concentrations of testosterone were not significantly different from the control group. However, plasma estradiol-17 concentrations of the female increased in Paralichthys olivaceus and Sebastes schlegeli after exposure. Our results suggest that 4-NP may disrupt the vitellogenesis system of immature fish by acting directly on vitellogenesis and steroidogenesis. Immature Sebastes schlegeli exposed with 4-NP were more sensitive than Paralichthys olivaceus and Pagrus major. There are obviously large inter-species differences in response of fish to 4-NP.