PARENT SESSION

2L (1) - Immunotoxicity - genotoxicity - ED
Hall 8
1:45 PM - 3:30 PM, Wednesday, 30 April 2003
Chair: Hansen, P.D.¹, ¹

(WE8/11) Assessment of endocrine disruptive effects of pharmaceuticals on non-biting midges (Chironomus riparius).

Weltje, Lennart¹, Vogt, Christian¹, van Doornmalen, Jacco¹, Markert, Bernd¹, Oehlmann, Jörg², ¹ International Graduate School (IHI), Zittau, Germany² J.W. Goethe University, Frankfurt am Main, Germany

ABSTRACT- The non-biting midge Chironomus riparius was used to assess the endocrine disrupting potential of four pharmaceuticals with different modes of action. The substances are: 17-ethynyl-estradiol (estrogen), tamoxifen (anti-estrogen), cyproterone acetate (anti-androgen) and 17-methyl-testosterone (androgen). Since the insect hormonal system differs from that of vertebrates, it is uncertain whether effects on sex-dependent parameters do occur. However, influences are expected on developmental parameters, since these are under control of a steroid hormone, i.e. 20-hydroxyecdysone. The primary route of exposure was water, with concentrations ranging from 0.01 to 100 nM. Each glass vessel contained a thin layer of quartz sand and 50 freshly hatched larvae, which were fed with ground TetraMin. Among the endpoints considered are number of emerged adults (mortality), sex-ratio, mean emergence time (EmT₅₀), adult body weight and egg production. Concentrations were mostly low enough not to cause any significant mortality. Changes in the sex-ratio (normally 1:1) were seldomly found. Males always emerged sooner than females and effects on the EmT₅₀ (either sooner or later than the control) were observed for both sexes and most substances. These effects were not necessarily concentration-dependent. Furthermore, adult body weight and egg production were clearly affected. These sex-dependent effects point towards an endocrine disruptive action of the selected pharmaceuticals.

Key words: emergence, Chironomus riparius, pharmaceuticals, endocrine disruption