AhR transcription serum activity of Inuit´s across Greenlandic districts

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  • Institute of Environmental and Occupational Medicine

Background: Human exposure to lipophilic persistent organic pollutants (POPs) including

Human exposure to lipophilic persistent organic pollutants (POPs) including

polychlorinated dibenzo-p-dioxins/furans (PCDDs/PCDFs), polychlorinated biphenyls

(PCBs) and organochlorine pesticide is ubiquitous. The individual is exposed to a complex

mixture of POPs being life-long beginning during critical developmental windows. Exposure

to POPs elicits a number of species- and tissue-specific toxic responses, many of which

involve the aryl hydrocarbon receptor (AhR). The aim of this study was to compare the actual

level of integrated AhR transcriptional activity in the lipophilic serum fraction containing the

actual POP mixture among Inuit's from different districts in Greenland, and to evaluate

whether the AhR transactivity is correlated to the bio-accumulated POPs and /or lifestyle

factors.

Methods: The study included 357 serum samples from the Greenlandic districts: Nuuk and

The study included 357 serum samples from the Greenlandic districts: Nuuk and

Sisimiut (South West Coast), Qaanaaq (North Coast) and Tasiilaq (East Coast). The bioaccumulated

serum POPs were extracted by ethanol: hexane and clean-up on Florisil

columns. Effects of the serum extract on the AhR transactivity was determined using the

Hepa 1.12cR mouse hepatoma cell line carrying an AhR-luciferase reporter gene, and the

data was evaluated for possible association to the serum levels of 14 PCB congeners, 10

organochlorine pesticide residues and/or lifestyle factors.

Results: In total 85% of the Inuit samples elicited agonistic AhR transactivity in a district

In total 85% of the Inuit samples elicited agonistic AhR transactivity in a district

dependent pattern. The median level of the AhR-TCDD equivalent (AhR-TEQ) of the

separate genders was similar in the different districts. For the combined data the order of the

median AhR-TEQ was Tasiilaq > Nuuk > Sisimiut > Qaanaaq possibly being related to the

different composition of POPs. In overall, the AhR transactivity was inversely correlated to

the levels of sum POPs, age and /or intake of marine food.

Conclusions: i) We observed that the proportion of dioxin like (DL) compounds in the POP

i) We observed that the proportion of dioxin like (DL) compounds in the POP

mixture was the dominating factor affecting the level of serum AhR transcriptional activity

even at very high level of non DL-PCBs; ii) The inverse association between the integrated

serum AhR transactivity and sum of POPs might be explained by the higher level of

compounds antagonizing the AhR function probably due to selective POP bioaccumulation in

the food chain.

Original languageEnglish
JournalEnvironmental Health: A Global Access Science Source
Volume6
Issue1
ISSN1476-069X
Publication statusPublished - 2007

    Research areas

  • dioxin-like serum activity, endocrine disruption

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