In teleost and avian species these cells occupy a structure outside the thyroid gland named the ultimopharyngeal body.

Parafollicular cells were previously believed to be derived from the neural crest based on a series of experiments in quail-chick chimeras.

[4][5] However, lineage tracing experiments in mice revealed that parafollicular cells are derived from the endoderm origin.

[6] Parafollicular cells secrete calcitonin, a hormone that participates in the regulation of calcium metabolism.

[7] Parafollicular cells are also known to secrete in smaller quantities several neuroendocrine peptides such as serotonin, somatostatin or CGRP.