Parathyroid Hormone and Parathyroid Glands: Location, Potential Problems, Condition and Medical Uses

What are they and what do they do?

Although there is less attention than thyroid hormones, parathyroid hormone remains important in the body. This hormone is connected to the levels of calcium in the blood.

Understanding this hormone and its role in the body helps you take charge of your health at the right time.

Parathyroid hormone helps prevent low levels of calcium by acting on bones, intestines and kidneys. In the bones, the hormone triggers the release of calcium reserves from the bones to the blood. This can lead to bone destruction.

In the intestines, parathyroid hormone helps with the metabolism of vitamin D. This, in turn, allows the body to absorb more of the calcium that it digests from food.

Finally, in the kidneys the hormone stops the release of calcium through the urine, while also increasing the production of vitamin D.

The parathyroid glands are small glands of the endocrine system that lie behind the thyroid. There are four parathyroid glands that are normally the size and shape of a grain of rice.

The sole purpose of the parathyroid glands is to regulate the level of calcium in our bodies within a very narrow range so that the nervous and muscular systems can function properly.

Although they are neighbors and both are part of the endocrine system, the thyroid gland and the parathyroid glands are not related in any other way. The only major disease of the parathyroid glands is the hyperactivity of one or more of the parathyroid glands; That is hyperparathyroidism.

The parathyroid glands are four small glands, located in the neck, that intervene in calcium levels.

The glands are about the size of a grain of rice (weighing approximately 30 milligrams and 3 to 4 millimeters in diameter).

These glands create the parathyroid hormone (HPT). The HPT raises the level of calcium in the blood to:

Breaking a bone (where a large amount of calcium is stored in the body) and causing the release of calcium.

Increase the ability to attract calcium in foods.

Increasing the kidney’s ability to have calcium that would be lost in the urine.

The normal parathyroid glands function like the thermostat in your home to keep calcium levels in the blood in a very tightly controlled range.

When the level of calcium in the blood is too low, the HPT is released so that the calcium level returns to normal.

When the calcium level is normal or becomes too high, normal parathyroids will stop releasing HPT. The proper balance of calcium is crucial for the normal functioning of the heart, nervous system, kidneys and bones.

Where are the parathyroid glands located?

The parathyroid glands are usually located in the neck behind the thyroid gland, although there are exceptions.

During the development of the fetus inside the uterus, the four parathyroids go from the head to the lower neck, and are usually close to the thyroid gland.

Even so, the parathyroids may not always continue in these ways and end up in other locations in the neck or chest, called “ectopic.”

Approximately 90% of the glands are in common places. In the superior parathyroid glands, the normal location is to the side and slightly behind in the upper part of the thyroid.

The upper parathyroid glands can be next to the esophagus (the first part of the digestive tract that transports food from the mouth to the stomach) or in the chest, and very rarely can be found inside the thyroid.

The lower parathyroid glands have to travel further during development and therefore can be found in a greater number of areas than the upper glands.

Most of the lower parathyroid glands are found near the lower part of the thyroid gland, but occasionally they can be found in the thorax, in the upper part of the neck by the jaw, inside the thyroid gland or next to the carotid artery.

Potential problems with the function of parathyroid hormone

Because the function of parathyroid hormone directly affects the levels of calcium in the blood, the inadequate 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 hypercalcemia, which increases calcium levels in the blood.

This does not cause obvious symptoms in mild cases, but if the levels rise too high it can cause digestive discomfort, constipation, depression, lethargy, weakness, joint pain and excessive thirst.

Hypercalcemia is typically discovered during routine blood tests.

Very little parathyroid hormone causes a rare disease called hypoparathyroidism, which leads to low levels of calcium in the blood. This is fairly easy to deal with with vitamin D and oral calcium tablets, once it is discovered.

Parathyroid condition important

Low level of calcium in the blood.

The low level of calcium in the blood is much less common, particularly when it is caused by a problem with the parathyroid gland. There are some conditions that are present from birth and are quickly detected and treated immediately.

The treatment must last a lifetime! Little by little, the body adapts to this lower level of calcium and the symptoms may be minimal, even if patients are not always faithful when taking their medication.

Questions about parathyroid hormone

Because parathyroid hormone problems rarely cause symptoms early in the disease, be sure to ask your doctor about parathyroid hormone levels when a routine blood test is done.

If your calcium levels are too low or too high, consider asking your doctor about parathyroid hormone. Possible questions include:

  1. Are parathyroid levels the culprits of my calcium levels?
  2. How can I treat this?
  3. What are the dangers of inadequate levels of calcium?

Medical uses

Parathormone (PHT) and its teriparatide equivalent

They are bone-forming agents and belong to a new class of drugs to treat osteoporosis.

Teriparatide injection (FORTEOMD) is the first drug in this category approved by Health Canada.

How does teriparatide work?

The continuous process by which a bone is renewed is called bone remodeling .

Teriparatide injection is a novel form during the process of bone turnover, whereby new bone is immediately generated in the skeleton before the old bone completely disintegrates while stimulating the work of osteoblasts (cells that form tissue osseous).

Efficacy of teriparatide injection

Teriparatide injection has been shown to increase bone density and reduce the risk of vertebral fractures and other fractures associated with osteoporosis.

Which patients can use the medication?

It is used by postmenopausal women with severe osteoporosis (therefore with a high risk of bone fracture) or people whose previous therapeutic products have caused intolerance or are ineffective.

Teriparatide also increases bone mass in men with primary osteoporosis or severe hypogonadism (low testosterone levels), and in people whose previous treatments for osteoporosis gave low results or triggered intolerance to such treatments.

It is also indicated to treat osteoporosis in men and women under sustained systemic corticosteroids and whose risk of fracture is greater.


The drug is administered as a subcutaneous injection in the hip or abdomen at a dose of 20 mcg (micrograms) per day. This medication is prescribed for a maximum duration of 24 months.

Overview of pharmacological treatments and their role in the prevention and treatment of osteoporosis

The main objective of pharmacological treatments is to reduce fractures. Some of these medications are also used to reduce the risk of developing osteoporosis.

Others, like preventive measures, aim to stop the additional loss of bone density.

The functioning of the bones

Bone is a living tissue that is constantly repairing itself. A new bone replaces an old bone.

The cells (osteoclasts) chew the old bone creating small cavities, while other cells (osteoblasts) form the bone tissue and fill these cavities with new bone. The body restores the bones and keeps them healthy in a natural way.

In a healthy young person, osteoclasts and osteoblasts work together to keep bones healthy.

However, in the mid-thirties, this process is no longer effective, as we gradually lose bone mass. This loss of bone thins the bones, weakens them and occurs more quickly in a person with osteoporosis.

If you have osteoporosis, you have already lost a significant amount of bone, and unless it is treated, it can trigger a very serious condition.

Choose the right treatment

Based on the scientific evidence, you will discuss with your doctor all available therapeutic options, assess the risks and benefits of each one and choose the appropriate treatment.

You may have to try different treatments before finding the one that suits you best.

Some people respond better to one drug than another, or have side effects with one drug while others do not (as soon as a side effect occurs, see your doctor).

The cost of medications is also a factor to consider. For some patients, this cost is reimbursed by the public medication plans.

Remember that treatment plans can be changed. The important thing is to find one that suits you.


HT or estrogen / progesterone, is commonly used to relieve the symptoms of menopause.

Hormone therapy is prescribed for a limited period of time to postmenopausal women to prevent and treat osteoporosis only in the presence of menopausal symptoms, such as hot flushes and night sweats.

How does hormone therapy work?

After menopause, the body produces much less sex hormones (estrogen and progesterone), which results in the loss of bone density .

The treatments with estrogen and progesterone are to supplement these hormones with the lowest rate needed to relieve the symptoms of menopause. These treatments are composed of estrogen alone or a mixture of estrogen and progesterone.

Who can receive hormone therapy?

Estrogen and progesterone treatments are used to prevent osteoporosis in postmenopausal women and menopausal women before age 45 (early menopause).

The estrogen / progesterone mixture is used to treat osteoporosis in postmenopausal women.

How is it administered?

Treatment with estrogen and / or progesterone is available in the form of tablets, patches or other dosing regimens. Except in cases of hysterectomy , progesterone should also be taken to decrease the risk of cancer of the uterus .

Are there any side effects?

Prolonged use of HT for the treatment of postmenopausal osteoporosis increases the risk of cardiovascular disease, stroke or invasive breast cancer.

It also results in an unfavorable risk / benefit ratio. As a first step, other treatment options can be considered.

Side effects can include depression , headaches, breast pain, premenstrual syndrome, skin irritation and weight gain. Menstrual bleeding may also occur.

Experimentation with dosage types, such as patches and tablets, may facilitate the elimination or reduction of side effects.

However, although the parathyroid hormone can complement a hormone therapy process, it is always suggested that the patient see their GP before starting a treatment or process with drugs such as hormone therapy.

Likewise, it is very important to avoid self-medication as much as possible.