Dioxin-like components in human breast milk collected from Hong Kong and Guangzhou

K. P. Lai, W. Li, Y. Xu, M. H. Wong, Chris K.C. Wong

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

22 Citations (Scopus)

Abstract

The H4IIE rat hepatoma cell line was employed as a cell model to screen 7-ethoxyresorufin O-deethylase (EROD)-TCDD equivalents (EROD-TEQ) of human breast milk samples collected from Hong Kong and Guangzhou, China. The screening methods employed a 96-well plate spectrofluorometer-EROD assay. For cell-line validation, our results demonstrated a dose-dependent increase in the Ah receptor-mediated response (i.e., CYP1A1 mRNA and EROD) of the cells upon exposure to a number of known Ah receptor agonists, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,7,8-tetrachlorodibenzothiophene, benzo[a]pyrene, and β-naphthaflavone. TCDD induced CYP1A1 mRNA and EROD was in a close positive correlation (r=0.98). For the screening of dioxin-like compounds, breast milk samples collected during lactation weeks 3-5 were used. One hundred (from Hong Kong) and 48 (from Guangzhou) breast milk samples were assayed, of which 65% and 68% of the samples, respectively, showed detectable dioxin-like activities using the H4IIE cell EROD screening method. For sixty-five samples from Hong Kong the mean EROD-TEQ values ranged from 58.1 to 96.5pg/g of milk fat for those aged 21-36 years while 32 samples from Guangzhou had mean values of 98.8-202.1pg/g of milk fat. In comparisons of the EROD-TEQ values for different age groups from both cities, there were no significant differences (P
Original languageEnglish
Pages (from-to)88-94
JournalEnvironmental Research
Volume96
Issue number1
DOIs
Publication statusPublished - Sept 2004
Externally publishedYes

Research Keywords

  • CYP1A1
  • Dioxin
  • EROD
  • H4IIE rat hepatoma
  • TCDD

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