Calcitonin
Calcitonin, a thyroid hormone, increases bone density by increasing bone uptake of calcium and decreasing bone breakdown by osteoclasts.
- functions
- regulation of expression
- consequences of overexpression
- consequences of underexpression
- signalling pathways
- structure
Function
High blood levels of calcium increase calcitonin release, facilitating its uptake by bone.
Calcitonin is particularly important for the growth and development of children, and once adulthood hits, response to calcitonin decreases.
While calcitonin is not necessary for normal calcium homeostasis, it acts to decrease plasma calcium levels in two ways:
- inhibits bone osteoclasts, decreasing calcium and phosphate resorption
- increases kidney excretion of calcium by decreasing tubular resorption
Calcitonin is being used as a treatment for osteoporosis, acting to reduce trabecular bone loss and risk of fracture.
Regulation of Expression
Calcitonin is produced by parafollicular (C) cells of the thyroid.
Consequences of Overexpression
Consequences of Underexpression
Signalling Pathways
Structure
Calcitonin is a 32 aa peptide