Analytical Sciences

Highly Sensitive Reporter Gene Assay for Dioxins in Human Plasma by Using Cycloheximide as an Enhancer Substance

Koichi SAITO,*1 Haruyuki MATSUNAGA,*2 Atsuko OHMURA,*3 Mikiko TAKEKUMA,*3 Yasuhiko MATSUKI,*4 and Hiroyuki NAKAZAWA*1

*1 Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University, 2-4-41 Ebara, Shinagawa, Tokyo 142-8501, Japan
*2 Environmental Health Science Laboratory, Sumitomo Chemical Co., Ltd., 3-1-98 Kasugadenaka, Konohana, Osaka 554-8558, Japan
*3 Biological Effect Research Group, Saitama Institute of Public Health, 639-1 Kamiokubo, Sakura, Saitama 338-0824, Japan
*4 Institute of Food Hygiene, Japan Food Hygiene Association, 2-5-47 Tadao, Machida, Tokyo 194-0035, Japan

A reporter gene assay (RGA) that uses a mouse liver recombinant Hepa1c1c7 containing the firefly luciferase gene was developed to screen for dioxins in human plasma. For a high-sensitivity method, the addition of cycloheximide to the culture medium brought about a fivefold increase in the sensitivity. The detection limit was 0.1 pg/μL/well. Aryl hydrocarbon receptor (AhR) binding affinity factors (AhR-BAF), calculated from the effect concentration 50 (EC₅₀) value, showed approximately the same values as those in WHO-TEF (2006). A significant correlation between RGA and the conventional gas chromatography/mass spectrometry (GC/MS) method was obtained.

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