|
(T/FF212) Do elevated vitellogenin levels due to xenoestrogen exposure necessarily imply feminization of male fish? Schwaiger, Julia1, Kalbfus, Wolfgang1, Lausterer, Ralph2, Braunbeck, Thomas3, Negele, Rolf Dieter1, 1 2 3 ABSTRACT- The presence of the egg yolk precursor vitellogenin (Vtg) in the plasma of male fish is widely used as a biomarker for estrogenic pollutants. The question remains however, whether this biochemical response implies further ecologically relevant alterations. In the present study, 3-year old rainbow trout were exposed to 1 and 10 Key words: nonylphenol, sewage works, vitellogenin, sex differentiation |
g/l of the xenoestrogen nonylphenol (NP). Fish of the same age, treated with a high dose of the synthetic estrogen ethinylestradiol (EE2), served as positive controls. Both directly exposed adults as well as their progeny were investigated concerning plasma Vtg levels, sex steroids and gonadal histology. Besides the laboratory experiments an active monitoring for estrogenic effects was performed, in which adult male rainbow trout and rainbow trout eggs were exposed simultaneously to environmentally relevant dilutions of several sewage treatment work (STW) effluents via a bypass system. The resulting Vtg levels in adults were compared to potentially occurring effects on sex differentiation in the juveniles. Both exposure to NP under laboratory conditions as well as to diluted effluents of STWs in the field resulted in significant elevated plasma Vtg levels in adult male rainbow trout. This effect did not correlate with alterations of the sex ratios neither in the progeny of exposed fish (NP laboratory study) nor in individuals exposed during the embryonal and larval stage to diluted STW effluents. Whether the low percentage of intersex occurring in the progeny of NP-exposed fish represents a transgenerational effect or just a normal feature within the scope of physiological variability has to be discussed.