Understanding Parathyroid Hormone (PTH) and Its Role in Calcium Regulation and Bone Health

Parathyroid hormone, referred to as PTH, is a hormone secreted by the parathyroid gland located in the neck region. This hormone is involved in several functions, including calcium regulation and bone health. Our body uses calcium to build and maintain bones, and PTH plays a crucial role in ensuring these processes happen successfully. In this blog post, we will look at PTH and its role in calcium regulation and overall bone health.

Calcium Regulation

PTH's primary role is in regulating calcium levels within the body. When calcium levels are low, PTH stimulates the bone's cells to break down the bone tissue, which releases calcium into the bloodstream. At the same time, PTH decreases the excretion of calcium through the kidneys. The increase in circulating calcium helps maintain the body's calcium levels within a normal range.

Role in Bone Health

PTH plays a crucial role in bone health's maintenance and growth, where it helps in both resorption and deposition of bone. Bone resorption is the breakdown of bone tissue, while bone deposition is the formation of new bone tissue. PTH increases bone resorption, which releases calcium stored in the bone, and helps maintain calcium levels in the blood. PTH also stimulates osteoblasts, which are bone building cells that deposit calcium and collagen into the bone matrix. Thus, PTH helps in bone remodeling and keeping bones healthy and strong.

Vitamin D Activation

PTH stimulates the production of active vitamin D in the kidneys, which is essential for calcium absorption in the gut. Vitamin D helps in the absorption of calcium from the diet and maintains calcium levels in the blood. Without enough vitamin D, the body cannot absorb enough calcium from the diet, which leads to a deficiency in calcium levels, increasing the risk of osteoporosis.

Disorders Related to PTH

Disorders related to PTH include primary hyperparathyroidism, which is the overproduction of PTH by the parathyroid gland, and hypoparathyroidism, where the parathyroid gland does not produce enough PTH. Primary hyperparathyroidism leads to high calcium levels in the blood, which can cause several health problems, including kidney stones, osteoporosis, and bone fractures. On the other hand, hypoparathyroidism leads to low calcium levels, which can cause muscle cramps, seizures, and tingling sensations.

Factors Affecting PTH

PTH levels in the blood are regulated by various factors, including calcium levels, vitamin D levels, and magnesium levels. When blood calcium levels are low, PTH production increases, increasing calcium levels in the blood. Similarly, when vitamin D levels are low, PTH production increases, leading to increased production of active vitamin D in the kidneys. Low magnesium levels can also decrease PTH production, leading to low calcium levels in the blood and bone loss.


Parathyroid hormone plays an essential role in regulating calcium levels in the body and maintaining bone health. Without PTH, our body would not be able to maintain calcium homeostasis, leading to a range of health problems. While disorders related to PTH can cause a range of issues, monitoring calcium levels and seeking medical assistance when necessary can help manage these disorders effectively. Understanding the role of PTH in the body can help us take better care of our bones and overall health, ensuring a healthy and happy life.