title: PCB-associated changes in mRNA expression in killer whales (Orcinus orca) from the NE Pacific Ocean.
abstract: Killer whales in the NE Pacific Ocean are among the world's most PCB-contaminated marine mammals, raising concerns about implications for their health. Sixteen health-related killer whale mRNA transcripts were analyzed in blubber biopsies collected from 35 free-ranging killer whales in British Columbia using real-time quantitative polymerase chain reaction. We observed PCB-related increases in the expression of five gene targets, including the aryl hydrocarbon receptor (AhR; r(2) = 0.83; p < 0.001), thyroid hormone α receptor (TRα; r(2) = 0.64; p < 0.001), estrogen α receptor (ERα; r(2) = 0.70; p < 0.001), interleukin 10 (IL-10; r(2) = 0.74 and 0.68, males and females, respectively; p < 0.001), and metallothionein 1 (MT1; r(2) = 0.58; p < 0.001). Best-fit models indicated that population (dietary preference), age, and sex were not confounding factors, except for IL-10, where males differed from females. While the population-level consequences are unclear, the PCB-associated alterations in mRNA abundance of such pivotal end points provide compelling evidence of adverse physiological effects of persistent environmental contaminants in these endangered killer whales.
authors: Institute of Ocean Sciences, Fisheries & Oceans Canada, P.O. Box 6000, 9860 West Saanich Road, Sidney, British Columbia V8L 4B2, Canada.
authors: Andrea H
authors: AH
authors: Buckman
authors: Nik
authors: N
authors: Veldhoen
authors: Graeme
authors: G
authors: Ellis
authors: John K B
authors: JK
authors: Ford
authors: Caren C
authors: CC
authors: Helbing
authors: Peter S
authors: PS
authors: Ross
mesh_terms: D000818:Animals; D004784:Environmental Monitoring; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D008297:Male; D010140:Pacific Ocean; D011078:Polychlorinated Biphenyls / Q000633:toxicity*; D012333:RNA, Messenger / Q000235:genetics*; D050685:Whale, Killer / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D011078:Polychlorinated Biphenyls