Lamprey--an excellent model for iron metabolism.

After 500 million years of evolution, lamprey is in a natural environment characterized by low temperature and high iron content, and its unique adaptive evolution mode has developed its organizational structure and life mechanism in the process of metamorphosis, which provides a new direction for people to further study the origin and evolution of life. Iron is one of the essential nutrients for the human body and plays an important role in metabolic processes, but when exceeded, it can lead to iron toxicity. For example, the serum iron concentration of pre-metamorphosis larvae is 149 times that of normal males, and the iron content in the liver of juveniles is about 2-3 times that of normal humans. Lamprey has a complete biochemical system to tolerate high concentrations of free iron in the body, and high expression of important genes for iron homeostasis, such as transferrin, ferritin heavy chain, superoxide dismutase, etc., improves iron transport, iron storage and antioxidant capacity. Lamprey has an IRE/IRP regulatory system, which is an important protection mechanism for lamprey to adapt to the high iron content environment in the organization. In addition, lampreys gradually form oral glands during metamorphosis and development, which become the unique iron metabolism organs of lampreys. In this review, we mainly summarize the distribution of iron in various tissues of lamprey and the potential mechanism of adapting to the content of iron in the body, so as to provide a theoretical basis for the subsequent search for the molecular mechanism of iron metabolism.