POMC and adrenal gland hyperfunction: If the initial screening results suggest hypercortisolism, second-line investigations such as serum ACTH measurement, the CRH stimulation test, the high-dose (8 mg) DST, the desmopressin stimulation test, and bilateral inferior petrosal sinus sampling (IPSS) may be required to confirm the diagnosis and differentiate between ACTH-dependent and ACTH-independent forms [6].