Comparison of short-term estrogenicity tests for identification of hormone-disrupting chemicals.
The aim of this study was to compare results obtained by eight different short-term assays of estrogenlike actions of chemicals conducted in 10 different laboratories in five countries. Twenty chemicals were selected to represent direct-acting estrogens, compounds with estrogenic metabolites, estrogenic antagonists, and a known cytotoxic agent. Also included in the test panel were 17beta++-estradiol as a positive control and ethanol as solvent control. The test compounds were coded before distribution. Test methods included direct binding to the estrogen receptor (ER), proliferation of MCF-7 cells, transient reporter gene expression in MCF-7 cells, reporter gene expression in yeast strains stably transfected with the human ER and an estrogen-responsive reporter gene, and vitellogenin production in juvenile rainbow trout. 17beta-Estradiol, 17alpha-ethynyl estradiol, and diethylstilbestrol induced a strong estrogenic response in all test systems. Colchicine caused cytotoxicity only. Bisphenol A induced an estrogenic response in all assays. The results obtained for the remaining test compounds--tamoxifen, ICI 182.780, testosterone, bisphenol A dimethacrylate, 4-n-octylphenol, 4-n-nonylphenol, nonylphenol dodecylethoxylate, butylbenzylphthalate, dibutylphthalate, methoxychlor, o,p'-DDT, p,p'-DDE, endosulfan, chlomequat chloride, and ethanol--varied among the assays. The results demonstrate that careful standardization is necessary to obtain a reasonable degree of reproducibility. Also, similar methods vary in their sensitivity to estrogenic compounds. Thus, short-term tests are useful for screening purposes, but the methods must be further validated by additional interlaboratory and interassay comparisons to document the reliability of the methods.
Andersen
H R
HR
Department of Environmental Medicine, Odense University, Denmark. hr.andersen@winsloew.ou.dk
Andersson
A M
AM
Arnold
S F
SF
Autrup
H
H
Barfoed
M
M
Beresford
N A
NA
Bjerregaard
P
P
Christiansen
L B
LB
Gissel
B
B
Hummel
R
R
Jørgensen
E B
EB
Korsgaard
B
B
Le Guevel
R
R
Leffers
H
H
McLachlan
J
J
Møller
A
A
Nielsen
J B
JB
Olea
N
N
Oles-Karasko
A
A
Pakdel
F
F
Pedersen
K L
KL
Perez
P
P
Skakkeboek
N E
NE
Sonnenschein
C
C
Soto
A M
AM
D003634:DDT / Q000633:toxicity; D004785:Environmental Pollutants / Q000633:toxicity*; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D004967:Estrogens / Q000378:metabolism / Q000633:toxicity*; D000431:Ethanol / Q000633:toxicity; D000077267:Fulvestrant; D006801:Humans; D011960:Receptors, Estrogen / Q000378:metabolism; D013629:Tamoxifen / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014819:Vitellogenins / Q000096:biosynthesis
D004785:Environmental Pollutants; D004967:Estrogens; D011960:Receptors, Estrogen; D014819:Vitellogenins; D013629:Tamoxifen; D000077267:Fulvestrant; D000431:Ethanol; D004958:Estradiol; D003634:DDT