yes, apparently the PVN or the paraventricular nuclues, is a part of the brain which controls adrenal function or release/supresses cortisol function is involved in what we call adrenal fatigue. Im guessing its dysfunctions is either a possible injury to the PVN or maybe its some type of fuse where it goes off as a protective mechanism but we somehow cant switch the power back on, thats just a guess though. Issues can still happen with the adrenal glands themselves but apparently its more likely the dysfunction of the PVN that causes low cortisol or irregular cortisol cycle. Im guess this adrenal dysfunction can occur on its own, maybe a burn out type situation and probably also occurs in many chronic conditions. In cfs/me i think its probably a down stream secondary issue, many of us test low in cortisol and or dhea, so its a common abnormality found through testing?