As far as I could gather, and it is documented all over the place where CAH is concerned, there is a direct association between a lack of cortisol and Growth Hormone being in excess as this stands to reason.  GH is needed for growth and growth is accelerated when kid’s don’t get enough cortisol on a day to day basis.  Rather like a child that has mild CAH or LOCAH.    It is also well known and documented that high cortisol suppresses growth---which means it as obviously suppressed the hormone that is responsible for growth, Growth Hormone.

What studies there are have not covered for our kids, a 24 hour profile when under treated over of the production of GH, 24 hr profile on an undertreated child with CAH or 24 hour profile on a child to find what the normal growth rate is or level of GH on 24 hour profile.  Or atleast a good range prodided for a similar age group as the under or over treated child that was tested.  

However, I don’t think it takes a rocket scientist to figure out what over and under treatment causes where GH is concerned given that when we look at the side-effects given for corticosteroids in excess, everywhere you look it states that it effects poor growth.  

Most Endo’s also know that corticosteroids suppress GH.  That is what all the new studies are about at the moment.  Common sense would also indicate it.  The only thing that stunts or accelerates a child’s growth is too much or too little of GH obviously.

GH is secreted all day long in pulses.  More so at night and at times of excercise than in the day when cortisol levels are somewhat higher.  Excercise causes a rise in cortisol, but initially there would be a dip before the rise which is probably where GH is secreted I would have thought. 

That is why most Doctors treating CAH like to use Hydrocortisone rather than more potent steroids.  Cortisol levels in normal healthy kids go up and down all day in peaks and troughs.  You can achieve that by giving 3-4 doses of cortisol per day 6-8 hours apart, and much better than you can achieve with one a day dex dose or twice a day pred dose, which must start of much much higher than the cortisol levels of a child on Hydrocortisone, and they probably stay higher for a much longer part of the day.  Thus, possibly suprressing more GH, especially if the theory is correct that corticosteroids suppress growth.  The average child on Hydrocortisone has probably had one or two troughs (or lows) where cortisol has achieved a low enough level to allow GH to be secreted closer to a similar amount that a normal healthy child would have had within the same time period.  :)