The endocrine system is a group of glands that secrete hormones into the circulatory system. The endocrine system helps maintain homeostasis by regulating the body's organs. Endothelial cells, smooth muscle cells, epithelial cells and fibroblasts are essential components necessary for the normal functioning of the endocrine system. For example, the pancreatic islets of Langerhans produce and secrete insulin and glucagon to maintain blood glucose levels. Atypical cell proliferation and regulation within the endocrine system contributes to the development of hypothyroidism, hyperthyroidism, diabetes, hypogonadism and cancer. We propose more than different types of normal human primary cells of the endocrine system such as pancreatic cells, adrenal cells and thyroid cells.