Several environmental chemicals are known to interact with functions related with the neuroendocrine system, and many of the endocrine disruptors present in the aquatic environment have estrogenic activity and can be responsible for feminization processes in wild fish and amphibians. The estrogenic effects of such disruptors include several levels of investigation: biological significance 'in vivo', and 'in vitro' by use of estrogenic biomarkers, and effects on the brain-pituitary-gonadal axis. Amphibians spend a great part of their life in the water, and can be considered 'sentinel species'; therefore, the effects of an estrogenic compound, 4-nonylphenol, were studied by 'in vivo' and 'in vitro' experiments. As a biomarker of estrogenic effects, vitellogenin changes were assayed in male frogs and newts; the plasma sex steroid trend was evaluated, and brain aromatase-like-immunoreactivity was described. 4-Nonylphenol treatment was able to induce plasma vitellogenin in male frogs and newts, changes in the secondary sexual characteristics, and increase of androgen plasma levels in the treated male newts. Moreover, a reduction in both the number of ARO-LI containing neurons and their immunolabeling intensity was seemingly observed in the more caudal cluster of aromatase containing cells or ventral infundibular nucleus. In conclusion, 4-nonylphenol seems to affect different targets variously involved in amphibian reproduction.
Amphibians as a model for studying xenoestrogen-dependent neuroendocrine disruption.
POLZONETTI, Alberta Maria;MOSCONI, Gilberto;PALERMO, Francesco Alessandro;
2004-01-01
Abstract
Several environmental chemicals are known to interact with functions related with the neuroendocrine system, and many of the endocrine disruptors present in the aquatic environment have estrogenic activity and can be responsible for feminization processes in wild fish and amphibians. The estrogenic effects of such disruptors include several levels of investigation: biological significance 'in vivo', and 'in vitro' by use of estrogenic biomarkers, and effects on the brain-pituitary-gonadal axis. Amphibians spend a great part of their life in the water, and can be considered 'sentinel species'; therefore, the effects of an estrogenic compound, 4-nonylphenol, were studied by 'in vivo' and 'in vitro' experiments. As a biomarker of estrogenic effects, vitellogenin changes were assayed in male frogs and newts; the plasma sex steroid trend was evaluated, and brain aromatase-like-immunoreactivity was described. 4-Nonylphenol treatment was able to induce plasma vitellogenin in male frogs and newts, changes in the secondary sexual characteristics, and increase of androgen plasma levels in the treated male newts. Moreover, a reduction in both the number of ARO-LI containing neurons and their immunolabeling intensity was seemingly observed in the more caudal cluster of aromatase containing cells or ventral infundibular nucleus. In conclusion, 4-nonylphenol seems to affect different targets variously involved in amphibian reproduction.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
