T6 PM Immune and Endocrine Disruption: Detection and Implication
Tuesday, 15 November 2005: 1:50 PM - 5:30 PM in 324-326

(LAV-1117-727902) The avian embryo bioassay for evaluating reproductive and immune disruption.

Lavoie, E¹, Quinn, Jr., M¹, Ottinger, M¹, ¹ University of Maryland, College Park, MD, USA

ABSTRACT- The avian embryo presents a self-contained system for studying the consequences of embryonic exposure to xenobiotics. This makes the avian embryo an appealing developmental bioassay subject for identifying effects from exposure to endocrine disrupting compounds (EDC). Investigators in our laboratory have used this bioassay in Japanese quail to evaluate endocrine disruption following exposure via egg injection to several EDCs, including estradiol, trenbolone, vinclozolin, methoxychlor, DDE, and 4-hydroxy-2′, 4′, 6′-trichlorobiphenyl . These studies have evaluated a number of endocrine, neuroendocrine and immune endpoints for determining endocrine disruption in hatchling, juvenile and adult Japanese quail. Endpoints include serum or fecal steroid hormones, histology and morphology of the bursa and gonad, hypothalamic aromatase activity, monoamine content and GnRH-I concentration. In adults, reproductive maturation, male mating behavior and immune function were also assessed. The sensitivity of each endpoint depended on the dosing regime, age at exposure, and class of chemical. Embryo mortality and hatchling hormone levels appear to be useful indicators of EDC impact but multiple endpoints appear to be necessary for detection of endocrine disruption in this bioassay since different chemicals have different modes of toxicity. This bioassay is being developed as a dose range finder for avian two generation toxicity tests and will serve as a useful first step for dietary studies of suspected EDCs in birds. This research was partially funded by Battelle Labs in support of a U.S. EPA contract.

Key words: Japanese quail, egg injection, endocrine disruption, immune disruption