PARENT SESSION
PT2 - Endocrine Disruption
Tuesday, 19 November 2002
8:00 AM to 6:30 PM
Exhibit Hall

(P549) Retinoic acid induces developmental abnormalities during amphibian metamorphosis.

Alsop, Derek^*,1, Brown, Scott², Van Der Kraak, Glen¹, ¹ University of Guelph, Dept. of Zoology, Guelph, ON, Canada² Aquatic Ecosystem Protection Research Branch, National Water Research Institute, Burlington, ON, Canada

ABSTRACT- Previous studies have shown that amphibian metamorphosis can be exquisitely sensitive to alterations in retinoic acid (RA) concentrations. Specifically, hindlimb development can be disrupted in the transformation of a tadpole into a frog when RA is added to the surrounding water. In addition, other studies have shown that the levels of RA and its precursors can change in response to xenobiotic exposure. This study set out to test whether deformities from RA exposure through the diet are similar to deformities which occur when tadpoles are exposed to xenobiotics in the lab or in the wild. Xenopus laevis tadpoles were exposed to 10 and 100 g RA/g food and allowed to progress through metamorphosis. Exposed tadpoles had reduced growth and increased time to metamorphosis. In addition, exposure to RA induced developmental abnormalities such as missing and fused hindlimb digits in 74% of the tadpoles fed 100 g RA/g food. Exposure to 10 and 100 g RA/g food also caused reduced or missing eyes in 49% and 11% of the animals, respectively. Exposure also induced curvatures of the spine. These effects are similar to deformities that can occur with exposure to xenobiotics, both in the lab and in the wild. Future studies will look at the effects of xenobiotic exposure on RA levels and deformities.

Key words: retinoic acid, metamorphosis, deformities, Xenopus laevis