a science question prompted by a thread in GD

[ensho]

re: human bodies that contain dioxin and man made hormones

we know and are still learning what each of these does to a human body

but

how do the two interact in a body - it must be different from a body just having one of them?

[SnowGoose]

1. Your question draws a very small box around the exposures.

You definitely have a rock-solid point, and what some call combinitorial toxicology is without doubt where we are heading and where we've always needed to go to make lab toxicology fully relevant (along with the gene/environment interactions that are all the rage these days).

To illustrate the difficulty, let me just draw your attention to your phrase "how do the two interact in a body".

First, even though people say "dioxin", it's really a class of compounds. There are 75 variants, and that's if you're only looking at the chlorine-containing ones. Given that there are also multiple hormones (both natural and exogenous), and that they can come from many sources, and you see the problem (as an example, I used to eat quite a bit of soy - being vegetarian I was looking for the protein. But the evidence is now clear that the isoflavones in soy have real, measurable estrogenic effects in males who at *much* less soy than me.).

So when you say that it's different with both of them than just one, it leaves out the reality that we all have multiple hormones (at levels that change constantly), and we virtually all have dioxins in our bodies.

We're not going to have this all figured out in our lifetimes.

[enki23]

2. Or anyone's lifetimes, really. And models won't solve that for us.

Nice post, by the way. All I can imagine is that our best bet is, as it always has been, to understand the mechanisms as best we can and infer from those for each given set of compounds whether we should be looking for particular sorts of synergy (or simply additive, particularly for hormone activity) effects. But, as someone who's at least dabbled in hormonally active compound SAR modeling, I have to say I'm pretty damned skeptical that we'll have sufficient biological understanding to make a reasonably predictive model for those immensely complicated sorts of interactions within our *great great great grandhildren's* lifetimes. Till we do, I think we're stuck in a reality that says, "if you suspect an interaction, I guess you'll have to test them together and find out". Combinatorial efforts with cell cultures etc. can only go so far.

[ensho]

3. thank you both for your replies, very interesting but

but wouldn't a study be about the known harmful dioxins and the 'man made' hormones (not natural hormones)interacting?

and not a study of all dioxins and all hormones, man made/natural - that would be silly.