Calcitonine et peptides apparentés

Mature calcitonin is a 32 amino acid peptide. It is the main peptide of a wide peptide family, i.e., CT gene-related peptides I and II (CGRP-I and II), adrenomedullin, amylin. These peptides have similar structures and actions on 7 transmembrane receptors. The higher levels of CT are found in thyroids. Despite more than 40 years of study the definitive physiologic role of CT remains unknown. Total thyroidectomy or gene invalidation in mouse models does not modify physiologic parameters. Nevertheless CT levels determination is of value for clinicians as a sensitive and specific marker of medullary thyroid carcinoma. In sepsis, procalcitonin has also a diagnostic and prognostic value. Moreover, in septic conditions, CT immmuno-neutralization is able to improve the prognosis as shown in animal models.