Calcitonin and somatostatin content of C cells in rat and human thyroid

C cells of the thyroid probably exert a paracrine control on follicular cells through secretion of peptides such as calcitonin and somatostatin. The aim of the present study was to investigate the expression of different peptides produced by C cells in rat thyroid and in the different morphological and pathological conditions of the human thyroid. Therefore we employed the immunohistochemical double-staining method using anti-calcitonin and anti-somatostatin antibodies. The results of this study show the presence of C cells containing calcitonin and C cells containing somatostatin exclusively in the rat and the human thyroid. This distinction with prevalence of one peptide on the other is maintained in the different morphological and pathological conditions of the human thyroid.