W3 PM Biomarkers
Wednesday, 16 November 2005: 1:50 PM - 5:30 PM in Ballroom 3

(POE-1117-441955) Evaluating testosterone metabolism in the invertebrate Neomysis integer (Crustacea; Mysidacea) as a biomarker for endocrine disruption.

Poelmans, S.¹, Verslycke, T.², Monteyne, E. ³, Roose, P.³, Noppe, H.¹, Verheyden, K.¹, Van Hoof, N.¹, De Brabander, H.¹, Janssen, C.⁴, ¹ Ghent University - Veterinary Public Health and Food Safety, Merelbeke, Belgium² Woods Hole Oceanographic Institution - Biology Department, Woods Hole, MA, USA³ Managment Unit of the North Sea Mathematical Models, Oostende, Belgium⁴ Ghent University - Ecology and Environmental Biology, Gent, Belgium

ABSTRACT- Compared to the vertebrates, steroid metabolism in the invertebrates has not been well investigated and documented. In this study, we evaluated the use of testosterone metabolism as a biomarker for endocrine disruption in mysid shrimp. Steroid metabolism, hormone synthesis, and detoxification/activation of xenobiotics are all processes that dependent on the action of cytochrome P450 (CYP) enzymes. Several endocrine disruptors are suspected of exerting their effects through disruption of normal CYP function. Consequently, alterations in steroid hormone metabolism by CYP modulators can be used as a biomarker to examine the potential effects of endocrine disruptors. The invertebrate mysid Neomysis integer was used to evaluate changes in testosterone metabolism following acute exposures to environmentally relevant CYP modulators: tributyltin, nonylphenol, benzo(a)pyrene, and subsequently to testosterone. Identification and quantification of testosterone and its metabolites was performed using liquid chromatography coupled with multiple mass spectrometry. The effects of the different CYP modulators on phase I and phase II testosterone metabolism are discussed and compared. We conclude that testosterone metabolism of N. integer can be used as a sensitive endpoint to detect endocrine disruption of certain chemicals after an acute exposure.

Key words: testosterone metabolism, Neomysis integer, cytochrome P450, LC-MSⁿ