calcitonin

Examples of calcitonin in the following topics:

• Thyroid Gland

  • The thyroid gland, the largest endocrine gland, is responsible for the production of the hormones T3, T4, and calcitonin.
  • Another hormone produced by the thyroid gland, thyrocalcitonin, or calcitonin, decreases the concentration of calcium in the blood.
  • Calcitonin is produced by parafollicular cells of the thyroid, either releasing hormones or inhibiting hormones.
  • Calcitonin functions to help regulate calcium concentrations in body fluids.
  • The location of the thyroid gland is in the neck below the larynx and in front of the trachea; it is the largest endocrine gland in the body, producing T3, T4, and calcitonin.

• Hormonal Control of Blood Calcium Levels

  • The hormone calcitonin, which is produced by the parafollicular (or C) cells of the thyroid, has the opposite effect on blood calcium levels as PTH.
  • Calcitonin decreases blood calcium levels by inhibiting osteoclasts, stimulating osteoblasts, and stimulating calcium excretion by the kidneys.
  • Calcitonin is most important in children (when it stimulates bone growth), during pregnancy (when it reduces maternal bone loss), and during prolonged starvation (because it reduces bone mass loss).
  • In healthy, nonpregnant, unstarved adults, the role of calcitonin is unclear.

• Parathyroid Glands

  • PTH opposes the effect of thyrocalcitonin (or calcitonin), a hormone produced by the thyroid gland that regulates calcium levels.
  • PTH and calcitonin work in opposition to one another to maintain homeostatic calcium levels in body fluids.

• Bone Remodeling and Repair

  • Hormones such as parathyroid hormone, growth hormone, and calcitonin are also required for proper bone growth and maintenance.