In contrast, functional pituitary adenomas (i.e., growth hormone [GH], adrenocorticotropic hormone [ACTH], thyroid stimulating hormone [TSH], and prolactin [PRL] adenomas or prolactinomas) secrete sufficient hormones to cause corresponding signs and symptoms of hyperprolactinemia, acromegaly, or Cushing’s syndrome. This evidence concerns the gene GH1 and pituitary gland adenoma.