Its not that the studies are bad, or aren't useful, but you have to look at the context- just because something increases or decrease estro in-vitro doesn't always mean it is going to carry over, and you also have to look at methods, cell lines, and the discussion/context of the study to really even be able to reach any type of conclusion. I see a lot of Pubmed ninjas on this board (and others) throwing around abstracts, which isn't bad, per se, but doesn't always tell the full story. Full text > abstract and the conclusions derived thereof- I admit I have been guilty of throwing out abstracts in the past in an effort to save time, etc., but it isn't any substitute for information provided by the full text.........this is why i have little faith in studies....it cost a lot of money to do a study, and there always seems to be someone with ulterior motives behind the money.....and like the saying goes...'you get what you pay for".
To your point bigt, always look for government or state-sponsored work; these tend to be much more conclusive and have less potential for bias; however, not all scientific work undertaken by drug companies is necessarily bad, or containing ulterior motives- in fact, I have seen some really good studies in this realm, especially when it comes to pharmacokinetic studies and QSAR (supp cos. won't ever do these)