Reversible Pituitary Dysfunction in a Patient with Cushing's Syndrome due to Adrenal Adenoma

A 45-year-old woman who complained of weight gain and irregular menstruation was diagnosed as having Cushing's syndrome due to a 3 cm sized left adrenal adenoma. She underwent left adrenalectomy, and she also underwent combined anterior pituitary tests before and 9 months after the surgery. The growth hormone and adrenocorticotropic hormone levels failed to respond to hypoglycemia before the surgery, but their responses recovered after the surgery. Cortisol and thyroid stimulating hormone failed to respond to hypoglycemia and thyrotropin releasing hormone (TRH) before the surgery, respectively, but these were improved after the surgery. Luteinizing hormone, follicle stimulating hormone, and prolactin adequately responded to gonadotropin-releasing hormone and TRH, respectively, before and after the surgery. However, the basal levels of these hormones were higher after adrenalectomy, suggesting that hypercortisolemia had a significant influence on all the pituitary hormones. (J Kor Soc Endocrinol 21:146~152, 2006)