Steroid analogs inhibit hormone binding by an extract from Nippostrongylus brasiliensis (Nematoda)

Endocrine disruption in nematodes: effects and mechanisms

This paper reviews the current knowledge on endocrine disruption in nematodes. These organisms have received little attention in the field of ecotoxicology, in spite of their important role in aquatic ecosystems. Research on endocrine regulation and disruption in nematodes, especially the more recent studies, concentrate mainly on one species, Caenorhabditis elegans. Although an endocrine system is not known in nematodes, there is evidence that many processes are regulated via hormonal pathways. As vertebrate hormones, such as steroids, may have endocrine functions in nematodes as well, endocrine disrupting chemicals (EDCs) defined for vertebrates may also be able to influence nematodes. The studies that are reviewed here, and own data showed that potential EDCs can affect nematodes on all organizational levels, from molecules to communities. It is concluded that nematodes, notably its prominent species C. elegans, are a promising organism group for the development of biomonitoring tools, provided that more mechanistic evidence is gathered on hormonal processes within these animals.

Detection of an estrogen receptor in two nematode species and inhibition of binding and development by environmental chemicals

The presence of estrogen receptors or binding proteins was demonstrated in the free-living nematode species Panagrellus redivivus and Caenorhabditis elegans by radioimmunoassay. Twenty-five nanomolar concentrations of toxaphene, dieldrin, and dieldrin plus nonylphenol significantly inhibited estrogen binding to the receptor in P. redivivus. Binding was inhibited but not significantly by 25 nM nonylphenol, toxaphene plus dieldrin, or toxaphene plus nonylphenol. The current research supports the hypothesis that dieldrin, nonylphenol, and toxaphene may mimic estrogen, altering the normal pathways of estrogen metabolism. Based on observations of secondary sex structures, estrogenic chemicals had no effect on sex ratios or growth in Panagrellus redivivus, but caused a reduction of fecundity in this nematode.