impt: many estrogenicity tests understated

[ttweed@wildrockies.org (Tony Tweedale)]

I've now rcvd. the article I believe I mentioned over a week ago, where I
said companies tested chem's for estrogenicity using mice they knew were
E-insensitive.  Turns out I was informed wrong about that, but it certainly
remains very possible that people/companys who tested for estrogenicity
using this highly popular CD-1 mouse strain knew the mice were
E-insensitive (apparantly, annimal strains bred for high fecundity (for
economic reasons) generally undergo some genetic changes to their
reproductive hormone systems).

Whether or not they were deliberately used, this study inevitably (my
reading) invalidates many such tests that turned out E-negative or "not a
strong estrogen".  Not that every such tested chem is automatically a
stronger estrogen (as interindividual, interspecies, interorgan, etc.
differences in E-activity exist), but w/out doubt, there will be a general
reclassifying of these chemicals as more estrogenic.  I'd guess it'll be a
major shift, and something to speak up about to make sure the retesting
happens.  Funny something this impt didn't hit the list.

J. Spearow et al. 'Genetic Variation in Susceptebility to Endocrine
Disruption by Estrogen in Mice' _Science_ 285:1259-61 (20 Aug. '99).  there
is a very interesting news story on the implications in the same issue
('News of the Week' sectn.).
--

Tony Tweedale

Causality is a concept not subject to empirical demonstration. -David Hume
(1711-'76)

Temperate but endangered planet.  Enjoys weather, northern lights,
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