|
SAFER WORLD a private independent international internet information network www.safer-world.org/ b-HCH |
|
contact: info@safer-world.org
|
A low-dose E study E Ulrich et al. 'Env. Relevant Xenoestogen Tissue Concentrations Correlated to Biological [ie estrogenic] Responses in Mice' _Env Health Perspectives_108:973-9 (10/00) ..these U. Indiana researchers found that low doses of beta-HexachloroCycloHexane & o,p-DDT, low enuf that a few were lower than the typical low ng/mL (roughly, ppb) concentrations in human blood, caused increases in epithelial uterine cell height & epithelial vaginal cell thickness (as estrogen does), in mice. Their lowest statistically significant effect doses, 42 ng/mL of b-HCH and 18 ng/mL of o,p-DDT were generally 1-2 orders of magnitude higher than human blood concentrations, and inside the range of some, especially pesticide workers. See Table 2.At increasing doses, D/R was linear, except b-HCH's uterine cell effect plateued at the higher doses used. While not a human test (and I'd say that estrogens can have very different effects in different tissues & animals), the authors say that mice have proved good models so far for approaching estrogenicity humans. Blood levels of the pesticides correlated w/ fat levels. b-HCH is not lindane, used as lice treatment--gamma-HCH is (tho the products contain all the different isomers). I don't know what uses b-HCH is registered for.Moreover they mention the Spearow study (_Science_ 285:1259-61 ('99)) showing that the CD-1 mice they (and hundreds, if not thousands of other E tests) used are E-insensitive (at least as to estrogenic effects in testes of makle mice). "This study is the first to measure tissue or blood concentrations of O[-]C[l] pesticide concentrstions and correlate them w/ esstrogenic responses in a laboratory animal." |
Copyright© 1998-2008 SAFER WORLD. All rights reserved |