Polychlorinated biphenyl exposure and corticosterone levels in seven polar seabird species

The role of polychlorinated biphenyls (PCBs) on exposure-related endocrine effects has been poorly
investigated in wild birds. This is the case for stress hormones including corticosterone (CORT). Some
studies have suggested that environmental exposure to PCBs and altered CORT secretion might be
associated. Here we investigated the relationships between blood PCB concentrations and circulating
CORT levels in seven free-ranging polar seabird species occupying different trophic positions, and hence
covering a wide range of PCB exposure. Blood P7PCB concentrations (range: 61e115,632 ng/g lw) were
positively associated to baseline or stress-induced CORT levels in three species and negatively associated
to stress-induced CORT levels in one species. Global analysis suggests that in males, baseline CORT levels
generally increase with increasing blood P7PCB concentrations, whereas stress-induced CORT levels
decrease when reaching high blood P7PCB concentrations. This study suggests that the nature of the
PCB-CORT relationships may depend on the level of PCB exposure.
Arctic
Antarctic
Birds
PCBs
Glucocorticoids
Stress