Parafollicular cells produce thyrocalcitonin hormone. This hormone helps in the regulation of serum calcium levels. Islet cells are responsible for the production of hormones such as insulin and glucagon. Adrenal cells are responsible for the production of hormones such as cortisol and aldosterone. Pituitary cells are responsible for the production of growth hormone, prolactin, and adrenocorticotropic hormone.Calcitonin is a 32-amino acid linear polypeptide hormone that is produced in humans primarily by the parafollicular cells of the thyroid gland, and in many other animals in the ultimopharyngeal body. Wikipedia