title: The diffuse neuroendocrine system: peptides, amines, placodes and the APUD theory.
mesh_terms: D001078:APUD Cells / Q000502:physiology*; D000818:Animals; D001717:Birds / Q000502:physiology; D002642:Chick Embryo; D006801:Humans; D051379:Mice; D018377:Neurotransmitter Agents / Q000502:physiology*; D051381:Rats
chemical_list: D018377:Neurotransmitter Agents