SREL Reprint #2340

 

 

 

Responsiveness of the hypothalamo-pituitary-interrenal axis in an amphibian (Bufo terrestris) exposed to coal combustion wastes

W.A. Hopkinsa,b M.T. Mendoncaa, J.D. Congdonb

aDepartment of Zoology and Wildlife, Auburn University, Auburn, AL 36849, USA
bSavannah River Ecology Laboratory, Drawer E, Aiken, SC 29802, USA

 

Abstract

To assess the responsiveness of the interrenal axis to stress, we injected toads exposed to coal combustion wastes and toads from an unpolluted reference site with adrenocorticotropic hormone (ACTH), as well as the vehicle alone (saline). Initial circulating levels of corticosterone in toads captured at the polluted area were significantly higher than levels in toads from the reference site. Corticosterone levels in toads from the polluted site remained high even after 2 weeks of laboratory acclimation and injection with saline. The results may suggest disruption of hepatic enzymes responsible for the metabolic clearance of steroid hormones. Injection of toads from the polluted site with ACTH had no effect on plasma corticosterone levels, whereas a similar treatment of toads from the reference site stimulated a marked increase in corticosterone. Our study provides evidence that toads exposed to coal combustion wastes may be less efficient at responding to additional environmental stressors.

Keywords: Amphibians; Toads; Pollutants; Coal combustion wastes; Hormones; Stress; Corticosterone; Adrenocorticotropic hormone

SREL Reprint #2340

Hopkins, W.A., M.T. Mendonca, and J.D. Congdon. 1999. Responsiveness of the hypothalamo-pituitary-interrenal axis in an amphibian (Bufo terrestris) exposed to coal combustion wastes. Comparative Biochemistry and Physiology Part C 122:191-196.

To request a reprint

 

 
http://srel.uga.edu www.uga.edu