I haven't studied the robustness of the pituitary or thyroid, but if they are like the adrenals, they don't wear out from over-use.
I think "AF" is a misdiagnosis of not getting enough calories to meet your body's needs. The more emotional, mental, or physical stress you have, the more calories you need. I totally agree people are over-stressed in our society and need to deal with that, but for most people, it has nothing to do with certain glands unable to keep up with demand and if that is the case, people are wasting their time and money trying to directly treat these glands with supplements or what not.
I can see that if a person is not eating enough to meet their body's needs, the body won't have enough raw materials for the glands to produce the amounts of hormones they are being signalled to produce, but that wouldn't be the fault of the glands.
I think people just need to get "adrenal fatigue" out of their vocabulary.