Neuroendocrine Tumors of the Thymus

Abstract

The endocrine system is the collection of glands that produce hormones which regulate metabolism, growth and development, sexual function, tissue function, reproduction, sleep, and mood, among other things. The endocrine system consists of the pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, ovaries (in females), and testicles (in males). In addition to endocrine glands, there are a large number of scattered endocrine cells in many other organs, which secreted hormone-like substances playing an important role in regulating physiological activities. In 1969, Pearse [1] named these endocrine cells with amine precursor uptake and decarboxylation (APUD) cells because they can synthesize and secrete amines, which are produced by decarboxylation of amine precursors (amino acids). With the continuous expansion of APUD cell types and distribution, it is found that many neurons in the nervous system also synthesize and secrete the same amines and/or peptides as APUD cells. Therefore, these neurons with secretory function (secretory neurons) and APUD cells are collectively called the diffuse neuroendocrine system (DNES). DNES is an expansion on the basis of APUD and it combined the nervous system and endocrine system as a whole body, which regulate and control the dynamic balance of the body’s physiological activities.