A 30-kDa protein synthesized primarily in the ANTERIOR pituitary gland and the hypothalamus. It is also found in the skin and other peripheral tissues. Depending on species and tissues, POMC is cleaved by PROHORMONE CONVERTASES yielding various active peptides including ACTH; beta-lipotropin; endorphins; melanocyte-stimulating hormones; and others (GAMMA-LPH; corticotropin-like intermediate lobe peptide; N-terminal peptide of POMC or NPP).