During conventional pharmacologic dose corticosteroid therapy, ACTH production is inhibited with subsequent suppression of cortisol production by the adrenal cortex. Recovery time for normal HPA activity is variable depending upon the dose and duration of treatment. During this time the patient is vulnerable to any stressful situation. Although it has been shown that there is considerably less adrenal suppression following a single morning dose of prednisolone (10 mg) as opposed to a quarter of that dose administered every six hours, there is evidence that some suppressive effect on adrenal activity may be carried over into the following day when pharmacologic doses are used. Further, it has been shown that a single dose of certain corticosteroids will produce adrenal cortical suppression for two or more days. Other corticoids, including methylprednisolone, hydrocortisone, prednisone, and prednisolone, are considered to be short acting (producing adrenal cortical suppression for 1¼ to 1½ days following a single dose) and thus are recommended for alternate day therapy.
Although I am usually not inclined to posit speculations on why a particular drug does or doesn't do something, in this case I will. Im guessing that the higher doses of Anadrol cause enough appetite suppression (at least anecdotally) to make eating rather difficult. It can also increase insulin resistance and glucose intolerance (5). This has the effect of making macronutrient absorption more inefficient, and could also be a factor in reducing gains when the dosage goes over 100mgs/day. Unfortunately, Anadrol also has a reasonably profound effect on your body's natural hormonal system, on par with most other oral steroids , but not as bad as most injectables, and its certainly not as harsh on your lipid profile as many anabolics are
Hydrocortisone belongs to a group of medicines called corticosteroids. It is sometimes referred to simply as an oral steroid. It is used as a replacement treatment for people whose adrenal glands are not producing as much of the steroid hormones (such as cortisol) as they normally do. This can happen in a condition known as adrenal insufficiency, or Addison's disease. It also happens in people who have had surgery to remove their adrenal glands and who therefore no longer make their own natural steroid hormones. These hormones are vital for your body and if you do not have enough of them, you can become very unwell.