Calcitonin

Definition

Calcitonin is a hormone produced by the thyroid gland that helps regulate calcium levels in the blood. It lowers blood calcium levels by inhibiting osteoclast activity and increasing calcium excretion in the kidneys.

5 Must Know Facts For Your Next Test

1. Calcitonin is secreted by the parafollicular cells (C cells) of the thyroid gland.
2. It acts to reduce blood calcium levels by inhibiting bone resorption and promoting renal excretion of calcium.
3. Synthetic calcitonin is used clinically to treat conditions like osteoporosis, Paget's disease, and hypercalcemia.
4. Calcitonin's effects are opposite to those of parathyroid hormone (PTH), which increases blood calcium levels.
5. The primary clinical forms of synthetic calcitonin are salmon calcitonin and human calcitonin.

Review Questions

• What cells produce calcitonin in the thyroid gland?
• How does calcitonin affect blood calcium levels?
• What are some clinical uses for synthetic calcitonin?

Related terms

Parathyroid Hormone (PTH): A hormone secreted by the parathyroid glands that increases blood calcium levels.

Osteoclasts: Bone cells that break down bone tissue, releasing minerals into the bloodstream.

Hypercalcemia: A condition characterized by an abnormally high level of calcium in the blood.