Age-related peptide production by human thyroid C cells. An immunohistochemical study

C cells of thyroid are known to express a variety of products beside calcitonin. These include the peptides PDN21 (katacalcin), calcitonin-gene related peptide (CGRP), bombesin and somatostatin. The expression of these products has been investigated by immunohistochemistry of thyroid tissue in six age ranges from fetal to late adult life. PDN 21 was found to have co-expression with calcitonin. CGRP and bombesin both demonstrated an age-related increase in numbers and intensity of cells stained. Somatostatin immunoreactivity was limited to small numbers of cells.