of research revealing hormonal
activity by various compounds
V, J Garey, MS Wolff and BGT Pogo. 1999. Estrogenic Potential
of Certain Pyrethroid Compounds in the MCF-7 Human Breast Carcinoma
Cell Line. Environmental
Health Perspectives 107:173-177.
Go et al. demonstrate convincingly that certain pyrethroid
pesticides are endocrine disruptors. They tested sumithrin,
fenvalerate, d-trans allethrin, and permethrin and found that
each of these pyrethroids disrupted estrogen signalling, although
the patterns of disruption varied among the compounds. Their
dose-response curves included several striking examples of non-monotonic
relationships, important because of their implications for regulatory
SC, FS vom Saal, KA Thayer, MG Dhar, M Boechler and WV Welshons.
1997. Relative binding affinity-serum modified access (RBA-SMA)
assay predicts the relative in vivo activity of the xenoestrogens
bisphenol A and octylphenol. Environmental Health Perspectives
This paper by Nagel et al.presents several important
establish that very low levels of bisphenol A, the basic
building block of polycarbonate plastic, when fed to female
mice during pregnancy cause the prostate of male offspring
to become signficantly larger than normal and hypersensitized
to subsequent hormonal stimulation.
determine that the amount of bisphenol A required to cause
this is comparable, relative to body weight, of ongoing
human exposure to bisphenol A:
are often referred to as weak estrogens that are not likely
to be biologically active at environmentally relevant concentrations.
In our study, a maternal dose of only 2 µg/kg/day bisphenol
A enlarged the prostate in male offspring. This dose is
equivalent to a daily dose of 50 µgs for a 25-kg child
or 150 µgs for a 75-kg adult. In this regard, Olea
et al. have shown that after a 50-mg dental sealant
treatment, the saliva measured in a 1-hr collection after
the application of the sealant from human subjects contained
from 90 to 931 µg of bisphenol A. They also measured
bisphenol A in the saliva of an individual who had tooth
sealant applied 2 years earlier and found 66.4 µgs
in a 1-hr saliva collection before additional sealnt treatment,
suggesting that bisphenol A may be continually released
after the initial dental work. Brotons et al. analyzed
vegetables packaged in food cans with lacquer coating and
found that as much as 23 µgs of bisphenol A was recovered
from 50 ml of the liquid portion of one food can."
report that serum
binding proteins are more effective at reducing the
biological activity of estradiol and octylphenol than of
bisphenol A. "The activity of bisphenol A was slightly enhanced
in serum while the activity of nonylphenol and octylphenol
was dramatically decreased relative to estradiol."
N, R Pulgar, P Perez, F Olea-Serrano, A Rivas, A Novillo-Fertrell,
V Pedraza, A Soto and C Sonnenschein. 1996. Estrogenicity
of resin-based composites and sealants used in dentistry.
Bisphenol A is a common ingredient in restorative materials
used in dentistry. Olea et al. report that some resin-based
compounds used as dental sealants to protect children from caries
leach bisphenol A and other compounds after application to teeth.
A significant portion of the leached materials is likely to
be absorbed by the intestine. Using standard tests, Olea et
al. determine that that the leached bisphenol A is estrogenic
at levels measured in saliva post-treatment.
P , R Pulgar, F Olea-Serrano, M Villalobos, A Rivas, M Metzlerl,
V Pedraza, and N Olea. 1998. The Estrogenicity of Bisphenol
A-related Diphenylalkanes with Various Substituents at the Central
Carbon and the Hydroxy Groups. Environmental
Health Perspectives 106(3):167-174 .
amazing discovery in this paper is that bisphenol-F is estrogenic.
What is astonishing about this is that bisphenol-F is produced
by a process patented in 1909 by LH Baekeland, involving the
reaction between phenol and formaldehyde. It was this process
that Baekeland discovered could be used to produce what he
called bakelite...or bisphenol F. Bakelite became the first
"miracle plastic" to move into global commerce,
used in an enormous variety of consumer products. Many people
can recall, for example, the smell of burning bakelite used
to make components of kitchen ovens. The implication is that
people have been exposed to synthetic estrogenic substances
since early in the 20th century.