Findlay D M
Department of Orthopaedics and Trauma, The University of Adelaide, Bice Building Royal Adelaide, Hospital, North Terrace, Adelaide, South Australia, Australia.
Cell Mol Biol (Noisy-le-grand). 2006 May 30;52(3):3-8.
Calcitonin (CT) is a 32 amino acid peptide hormone of thyroidal origin, whose main recognised physiological role is the inhibition of osteoclast--mediated bone resorption. There is also evidence that CT might modulate bone formation. However, both CT and its receptors (CTR) have also been identified in a large number of other cell types and tissue sites, suggesting roles for the CT/CTR system distinct from those involving calcium homeostasis. Evidence has accumulated consistent with the involvement of CT in cell growth and differentiation and in tissue development and remodelling. The close proximity of cells expressing CT, or CT receptors (CTR), during development, and during pregnancy and lactation, is consistent with important roles for CT in morphogenesis. It thus appears that, in tissues such as the uterus, breast and pituitary, CT acts in a paracrine manner to Influence cell proliferation and function, as distinct from its endocrine actions to regulate calcium stores in the skeleton. In vitro studies have shown that CT can be either mitogenic or can inhibit cell proliferation, depending on the cell type and the conditions of the experiment. More recently, evidence has also been obtained for a role for CT in cell survival, in cells as diverse as osteoblast--like and osteocyte--like cells, osteoclasts and neurons.
降钙素（CT）是一种起源于甲状腺的由32个氨基酸组成的肽类激素，其主要公认的生理作用是抑制破骨细胞介导的骨吸收。也有证据表明降钙素可能调节骨形成。然而，降钙素及其受体（CTR）也已在大量其他细胞类型和组织部位中被鉴定出来，表明降钙素/降钙素受体系统具有不同于涉及钙稳态的作用。越来越多的证据表明降钙素参与细胞生长和分化以及组织发育和重塑。在发育过程中以及妊娠和哺乳期，表达降钙素或降钙素受体（CTR）的细胞紧密相邻，这与降钙素在形态发生中起重要作用相一致。因此，在子宫、乳腺和垂体等组织中，降钙素以旁分泌方式发挥作用，影响细胞增殖和功能，这与其调节骨骼中钙储备的内分泌作用不同。体外研究表明，根据细胞类型和实验条件，降钙素既可以是促有丝分裂的，也可以抑制细胞增殖。最近，也有证据表明降钙素在成骨样细胞、骨细胞样细胞、破骨细胞和神经元等多种细胞的细胞存活中发挥作用。
