REPTILES AS MODELS OF CONTAMINANT-INDUCED ENDOCRINE DISRUPTION

Historically, reptiles have been used as bioindicators of environmenta l contaminants and, currently, reptiles have the potential to elucidat e the mechanisms of a newly described group of environmental contamina nts-endocrine disrupters. Reptiles are particularly good models for st udying endocrine altering compounds due to the fact that different spe cies of reptiles have varying modes of gender determination (genotypic sex determination or temperature-dependent sex determination) and par ity modes (oviparity or viviparity). This review focuses both on labor atory and field studies of contaminant-induced endocrine alterations i n reptiles. Laboratory studies of oviparous reptiles with temperature- dependent sex determination reveal that embryonic exposure to natural hormones and many man-made chemicals (including the ubiquitous PCBs an d common herbicides) can permanently alter the functioning of the repr oductive system. It is hypothesized that similar permanent, organizati onal changes occur in wild reptiles exposed to endocrine-disrupting co ntaminants. (C) 1998 Elsevier Science B.V. All rights reserved.