Functioning pituitary adenoma leads to hypersecretion of hormones that results in classic clinical syndromes, mainly acromegaly (overproduction of GH), hyperprolactinemia (excess of PRL), and Cushing's disease (overproduction of ACTH) and, more rarely, secondary hyperthyroidism (increased TSH secretion). This evidence concerns the gene POMC and pituitary gland adenoma.