PARENT SESSION
WP2 - Toxicology Wildlife: Management Decisions
Chair: Halbrook, Richard1, 1 Southern Illinois University, Carbondale, IL, USA
Co-chair: Smits, Judit2, 2 University of Saskatchewan, Saskatoon, SK, Canada
2:10 PM to 5:30 PM - Wednesday, 20 November 2002
Room Ballroom J
(590) Development of a Reptile Model for Terrestrial Wildlife Ecotoxicological Studies.
Janz, David*,1, Talent, Larry1, Brasfield, Sandra1, Redick, Melinda1, Weber, Lynn1, 1 Oklahoma State University, Stillwater, OK, USA
ABSTRACT- There is a recognized need to develop laboratory reptile model(s) for ecotoxicological research and ecological risk assessments. Fence lizards (Sceloporus sp.) may represent a suitable reptile model due to their small size, rapid maturation, high fecundity and tolerance of laboratory conditions. In addition, fence lizards inhabit a wide range of habitats and are among the most widely distributed and common North American lizards. The long term objectives of our ongoing work with fence lizards are to (1) collect baseline toxicological and physiological data in laboratory-reared lizards, (2) utilize lizard eggs as a terrestrial vertebrate model for assessing bioavailability and developmental toxicity of soil contaminants, and (3) develop a two-generation reptile reproduction bioassay. Thus far, we have (1) described dose-response relationships for vitellogenin induction following exposure of male lizards to ethinylestradiol, (2) evaluated effects of early in ovo exposure to ethinylestradiol on sex ratios and development of secondary sexual characteristics, (3) determined seasonal and diel variation in circulating sex steroid and thyroid hormone levels in captive-reared lizards, and (4) characterized whole body thyroid hormone concentrations during the perinatal period. Our current focus is on development of a lizard egg screening assay for endocrine disrupting chemicals. Future applications of this research may involve both laboratory and field-deployable methods using eggs, juveniles, and/or adult fence lizards to aid in assessing ecological risk associated with exposure to single chemicals and complex environmental mixtures of toxicants.
Key words: reptile, estrogenic, thyroid, egg