Actually, I believe the answer to question #1 would be, "No." I asked essentially this same question of my son’s peds endo awhile ago.  One of his subspecialties within ped. endocrinology is circadian rhythm, so I tend to believe what he tells me on this.    

From what I understand, circadian rhythms persist, in spite of individual daily variations.  So, it doesn’t matter if you are an adult going to bed at midnight and sleeping 6 hours a night; or an infant going to bed at 8 pm sleeping 10 hours a night; or if your schedule varies from day to day---ACTH will still start to rise at ~3am, and peak at ~8 am.  Yes, ACTH levels will rise and fall throughout the course of the day, in response to many different stimuli---including sleeping, eating, stress, etc.--but those daily variations will not reset our underlying alarm clock. I think it has to do with how our brains have been programmed, over time, to respond to ~24-hour cycles of light and dark. 

I think this makes sense given that specific times are always stated in articles which talk about the circadian rhythm of ACTH and cortisol production.   I’m sure this would not be the case, if it was relative to an individual’s schedule.

Also, re. some of your other questions/comments, Sue:

2) I think it is pretty well accepted that excessive amounts of glucocorticoids will stunt growth.  But, I do not think it is a direct cause-effect relationship. Part of it has to do with how GH inhibits the action of GH binding protein at the site of the epiphyses.....or something like that.  I really don’t understand it all...I wish I did!  The only point I am trying to make is that the mechanism by which glucocorticoids inhibit growth is not one that appears to be completely understood by scientists and researchers.  So, thinking that the issue is as simple as not giving steroids at certain hours when GH secretion is at its peak is probably grossly oversimplifying the matter, and not necessarily accurate. 

5)  Levels of 17-ohp generally fall precipitously, in response to the morning dose.  So, yes, I think it is completely possible to get the wrong idea of suppression, if one tests after taking meds.  It is two slightly different approaches....trying to figure out how IN control you are, when control is at its BEST.  Or trying to figure out how OUT of control you are, when control is at its WORST.   One can probably make an argument for doing it either way, but I think there is good reason why most peds. endos seem to prefer the first way...BEFORE meds.  At the very least, I think one needs to have different standards of control, depending on whether or not meds were given before or after blood was drawn, as I think the numbers can vary by about three-fold.  

6)  Babies are supposed to grow ~25-30 cms (~10-11) inches the first year of life.  If your daughter has grown ~ 9 inches in 9 months, then she sounds to be doing pretty well. Genetics probably plays the biggest part in determining how tall a child will end up, but I don’t think there’s any reason to believe that your daughter is genetically predisposed to being smaller than average.  I believe the average height of an adult North-American male is 5’-9." For an adult woman, I think it is 5’-4."  You and your husband are both of average height, so I don’t think there is any reason to think that your daughter should be any less than that, under normal circumstances.  When assessing normal vs. abnormal growth, I think the key is  to look at the PATTERN of growth.....if things are okay, growth should more-or-less parallel the lines that you see on the standardized growth charts.  When the curve is too sharp, you may be seeing abnormally rapid growth.  When it is too flat....abnormally slow growth.

Questions 3 & 4 would probably take an entire page on their own to discuss, and I’ve probably blabbed on long enough, so willl take a breath for now.  For what it’s worth, Sue, I think these are really good questions.  It IS very difficult to know what to think, at times.....some issues will probably clarify over time.  Other questions will probably always remain. Unfortunately, this appears to be the nature of the beast.