What is Parathyroid Hormone?


Although it gets less attention than thyroid hormones, the parathyroid hormone is still important in the body. Parathyroid hormone is connected to blood calcium levels.

Parathyroid hormone comes from four parathyroid glands in the neck, just behind the thyroid. These glands receive feedback from blood calcium levels to determine when they need to secrete the hormone. The hormone plays a role in regulating blood calcium levels, helping the body maintain adequate calcium stores in the bloodstream to protect bone health.

What does the parathyroid hormone do?

Parathyroid hormone helps prevent low calcium levels by acting on the bones, intestine, and kidneys. In the bones, the hormone triggers the release of calcium stores from the bones to the blood. This can lead to bone destruction. In the intestines, parathyroid hormone helps with vitamin D metabolism. This, in turn, allows the body to absorb more of the calcium it digests from food. In the kidneys the hormone stops the release of calcium through the urine, while also increasing vitamin D production.

Potential Problems with Parathyroid Hormone Function

Because the function of parathyroid hormone directly impacts blood calcium levels, improper balance of parathyroid hormone can cause an imbalance of calcium levels in the blood.

Having too much of the hormone can cause a condition known as hypercalcaemia, which increases blood calcium levels. This does not cause obvious symptoms in mild cases, but if levels rise too high, it can cause digestive upset, constipation, depression, lethargy, weakness, joint pain, and excessive thirst. Hypercalcaemia is typically discovered during routine blood testing.

Too little parathyroid hormone causes a rare condition called hypoparathyroidism, which leads to low blood calcium levels. This is fairly easy to treat using vitamin D and oral calcium tablets, once it is discovered.

Questions to ask your doctor

Because parathyroid hormone problems rarely cause symptoms at the beginning of the condition, be sure to ask your doctor about parathyroid hormone levels when having routine blood work done. If calcium levels are too low or too high, consider asking your doctor about parathyroid hormone. Possible questions include:

  • Are parathyroid levels to blame for my calcium levels?
  • How can I treat this?
  • What are the dangers of improper calcium levels?

If you suspect parathyroid hormone problems, get help from an endocrinologist near you.

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