IGF1 and pituitary gland adenoma: Growth hormone-secreting pituitary adenoma (GHPA) is due to the overproduction of growth hormone (GH) by pituitary adenomas, which stimulates the liver to produce insulin-like growth factor 1 (IGF-1), and the long-term overproduction of GH and IGF-1 promotes the overgrowth of soft tissues, bones, and cartilages throughout the body, leading to a series of typical signs and symptoms of acromegaly or gigantism, and can cause multi-organ/system complications such as respiratory, cardiovascular, digestive system, and glucose metabolism.