A 47-year-old patient is admitted to the

intensive care unit due to severe infection or sepsis. A number of parameters

are used to monitor the development of inflammation and the patient's general

condition. One of them is procalcitonin. This protein is physiologically

produced by thyroid cells as a precursor to the hormone calcitonin. However,

especially in generalized bacterial infections, other cells, mainly

neuroendocrine cells of the lung and intestine, start to produce it. The

concentration of this protein then rises sharply in the plasma. What are the

name of thyroid cells that produce this protein?