Calcitonin and Bone Physiology: In Vitro, In Vivo, and Clinical Investigations

Abstract

Calcitonin was discovered as a peptide hormone that was known to reduce the calcium levels in the systemic circulation. This hypocalcemic effect is produced due to multiple reasons such as inhibition of bone resorption or suppression of calcium release from the bone. Thus, calcitonin was said as a primary regulator of the bone resorption process. This is the reason why calcitonin has been used widely in clinics for the treatment of bone disorders such as osteoporosis, hypercalcemia, and Paget’s disease. However, presently calcitonin usage is declined due to the development of efficacious formulations of new drugs. Calcitonin gene-related peptides and several other peptides such as intermedin, amylin, and adrenomedullin (ADM) are categorized in calcitonin family. These peptides are known for the structural similarity with calcitonin. Aside from having a similar structure, these peptides have few overlapping biological activities and signal transduction action through related receptors. However, several other activities are also present that are peptide specific. In vitro and in vivo studies documented the posttreatment effects of calcitonin peptides, i.e., positive effect on bone osteoblasts and their formation and negative effect on osteoclasts and their resorption. The recent research studies carried out on genetically modified mice showed the inhibition of osteoclast activity by amylin, while astonishingly calcitonin plays its role by suppressing osteoblast and bone turnover. This article describes the review of the bone, the activity of the calcitonin family of peptides, and the link between them.

The Effect of Space Travel on Bone Metabolism: Considerations on Today’s Major Challenges and Advances in Pharmacology

“…Calcitonin is a 32-amino acid linear polypeptide usually produced in humans primarily by the parafollicular cells of the thyroid gland. It acts as an osteoclast-inhibiting hormone, and today, salmon calcitonin is a currently FDA-approved medication as a second-line drug for postmenopausal osteoporosis and as a first-line treatment for hypercalcemia and Paget’s illness [ 76 , 77 ]. Focusing on calcitonin antiresorptive activity, the binding of this hormone to its receptor (calcitonin binding receptor or CTR) induces a rapid cell contraction and, therefore, causes inhibition of osteoclast motility which negatively affects cell capacity to resorb bone surfaces.…”

Identification and Functional Annotation of Genes Related to Bone Stability in Laying Hens Using Random Forests

“…In our study, the calcitonin receptor gene ( CALCR ) was identified as a strong candidate for BMD. Calcitonin plays a role in calcium homeostasis and is primarily an inhibitor of bone resorption [ 68 ]. Our observations are in line with previous reports, as CALCR polymorphisms were associated with site-specific BMD in humans [ 56 , 69 ], and alpha-calcitonin gene-related peptide deficient mice were shown to have a lower bone mass [ 70 ].…”

The Development of Molecular Biology of Osteoporosis

“…Calcitonin reduces calcium levels in the systemic circulation through the inhibition of bone resorption or prevention of calcium release from the bone. Therefore, calcitonin is used for the treatment of various bone disorders, including osteoporosis [ 150 ]. Salmon calcitonin is analogous to human calcitonin and is used in the treatment of post-menopausal osteoporosis.…”