From the research I am doing on the 10x theory, I have found nothing that supports this claim that 10x the dose should equal serum blood levels. Occam's Razor seems to be in affect here without a solid cogitated formula for our basis.
This study demonstrates some what of what we are looking for:
http://press.endocrine.org/doi/figure/10.1210/jcem.84.10.6078
http://press.endocrine.org/doi/full/10.1210/jc.2004-1184
and yes, this one again too:
http://ajpendo.physiology.org/content/281/6/E1172##
I have been corresponding with two of the Doctors in these studies. I directly asked them both if a rule of thumb 5x rule could be applied (I used 5x to see the reaction). One answer "It depends on the population - see again, the comparison our dose-response study for older men. Concentrations and effects can be much higher in older men ." My follow up question was how high, 10x???. Her response "that may too be high, but it is hard to determine because of the all variables involved." I haven't had a chance to follow it up. But I will.
My correspondence continues and hopefully I will learn more but I am swamp with my REAL job. lol. Feel free to follow up.
I've delved into this and I am only scratching the surface.