What is Calcitonin?
Calcitonin is an important hormone in human metabolism. It lowers the level of calcium and phosphate in the blood by influencing bone and kidney cells. Its counterpart is the parathyroid hormone, which accordingly increases the calcium and phosphate in the blood.
How is calcitonin produced?
Calcitonin is composed of 32 different amino acids (protein building blocks). It is produced in special thyroid cells, the so-called C cells. Other organs that produce calcitonin to a lesser extent are the parathyroid gland and the thymus. If the calcium level in the blood rises sharply, the C cells secrete the calcitonin formed. The hormone is excreted mainly by the kidneys.
Calcitonin action
The so-called osteoclasts, the bone-eating cells, are responsible for the breakdown of bone substance. Through their activity they release calcium and phosphate from the bone into the blood. Calcitonin inhibits these bone-degrading cells so that less calcium and phosphate is released from the bones and enters the blood – calcium and phosphate levels drop.
Because of its mode of action, physicians use calcitonin in the treatment of osteoporosis (bone loss) and Paget’s disease. In people with Paget’s disease, bone remodeling is disturbed and inferior bone material is formed. Patients suffering from pain due to bone metastases or bone cancer are also often given calcitonin.
When is calcitonin determined?
The blood level of the hormone is determined in cases of unexplained diarrhea, among other things. In addition, calcitonin is a tumor marker for medullary thyroid carcinoma, which originates from the so-called C cells: this tumor produces the hormone, which causes its concentration in the blood to rise. For this reason, the doctor determines the calcitonin level when a patient has a so-called cold nodule in the thyroid, or in cancer patients as the disease progresses.
Calcitonin standard values
To determine the level of the hormone, the doctor needs a blood sample. The normal concentration depends on gender:
|
Values in pg/ml |
|
|
Men |
< 11,5 |
|
Women |
< 4,6 |
When is the calcitonin level decreased?
When the calcium level in the body is too low, the calcitonin concentration is also correspondingly low. However, this is not a disease.
When is the calcitonin level elevated?
What to do if calcitonin levels change?
If the family doctor or hormone specialist (endocrinologist) detects an elevated calcitonin level, he or she will investigate the cause. Above all, a malignant thyroid tumor must be ruled out as the reason for the elevated calcitonin level. This can be done, for example, by imaging procedures such as CT and MRI or by taking a tissue sample.