Hi golfwidow-ga -
In searching the National Library of Medicine's Pub Med site, I found
no reference to a study, but did find this comment by a number of
researchers at the University of Zurich, one of whom is M. Schlumpf.
The comment is entitled "In vitro and in vivo estrogenicity of UV
screens," and is reported by M. Schlumpf M, B. Cotton, M.
Conscience, V. Haller, Steinmann B, and W. Lichtensteiger. It
appeared in the March 2001 issue of Environmental Health
Perspectives.
Researchers often write these so-called comments when they are in the
midst of research but do not yet have conclusions to report. This
could be because they haven't completed their studies or because they
have only a few research subjects.
The University of Zurich comment refers to the concern of the
researchers that the use of Ultraviolet screening products could have
an unintended side effect of increasing estrogenic activity. Using
breast cancer cells growing under artificial conditions, i.e. not
within an animal, they found that five of six chemicals used in
sunscreens caused the cells to multiply faster than would have been
otherwise expected. This is something that estrogen would do, hence
the effect is called estrogenicity.
In another example, they found that one of the chemical's effects was
blocked by an estrogen antagonist, that is a chemical that stopped
estrogenic activity. They inferred from this that if a chemical was
blocked by an anti-estrogen, it could well have estrogen-like
properties.
In still another example, the reseasrchers reported that several of
the sunscreen ingredients caused uterine weight to increase in rats.
The authors of this research comment state that their "findings
indicate that UV screens should be tested for endocrine activity, in
view of possible long-term effects in humans and wildlife."
The entire comment is printed below:
"Ultraviolet (UV) screens are increasingly used as a result of growing
concern about UV radiation and skin cancer; they are also added to
cosmetics and other products for light stability. Recent data on
bioaccumulation in wildlife and humans point to a need for in-depth
analyses of systemic toxicology, in particular with respect to
reproduction and ontogeny. We examined six frequently used UVA and UVB
screens for estrogenicity in vitro and in vivo. In MCF-7 breast cancer
cells, five out of six chemicals, that is, benzophenone-3 (Bp-3),
homosalate (HMS), 4-methyl-benzylidene camphor (4-MBC),
octyl-methoxycinnamate (OMC), and octyl-dimethyl-PABA (OD-PABA),
increased cell proliferation with median effective concentrations
(EC(50)) values between 1.56 and 3.73 microM, whereas
butyl-methoxydibenzoylmethane (B-MDM) was inactive. Further evidence
for estrogenic activity was the induction of pS2 protein in MCF-7
cells and the blockade of the proliferative effect of 4-MBC by the
estrogen antagonist ICI 182,780. In the uterotrophic assay using
immature Long-Evans rats that received the chemicals for 4 days in
powdered feed, uterine weight was dose-dependently increased by 4-MBC
(ED(50 )309mg/kg/day), OMC (ED(50) 935 mg/kg/day), and weakly by Bp-3
(active at 1,525 mg/kg/day). Three compounds were inactive by the oral
route in the doses tested. Dermal application of 4-MBC to immature
hairless (hr/hr) rats also increased uterine weight at concentrations
of 5 and 7.5% in olive oil. Our findings indicate that UV screens
should be tested for endocrine activity, in view of possible long-term
effects in humans and wildlife." " Environ Health Perspect 2001
Mar;109(3):239-44
Pub Med Search Terms: Schlumpf estrogen
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=Index&DB=PubMed
Good luck,
Alanna |
