Parathyroid (PTH) hormone is released when there are low calcium levels in the body. PTH regulates calcium to acceptable levels. Elevated PTH levels occur because of abnormal secretion of the hormone from the parathyroid gland located in the neck. The connection between parathyroid hormone and osteoporosis is that abnormal PTH levels ultimately lead to osteoporosis. A medical treatment called parathyroid hormone therapy can prevent the bone damage that leads to osteoporosis.
PTH is manufactured by the parathyroid glands, which are tiny glands located behind the thyroid gland. When a person’s the blood calcium levels fall too low, the parathyroid glands send out extra PTH. This results in the bones releasing additional calcium into the blood, while at the same time reducing the levels of calcium released by the kidneys into the urine. Vitamin D is then converted into a more active form, which causes the absorption of more calcium into the intestines.
Sometimes, through disease or malfunction, the parathyroid gland releases continuous or unwarranted amounts of PTH. This causes a loss of bone mass, eventually resulting in osteoporosis. Paradoxically, PTH therapy uses parathyroid hormone to build bone mass rather than decrease it, reversing the previously destructive relationship between parathyroid hormone and osteoporosis.
Researchers that developed PTH therapy discovered that when a synthetic parathyroid hormone was administered in “pulses” — controlled daily injections — it worked to stimulate an increase in bone mass rather than to destroy it and increased bone strength as well. The treatments involve teriparatide, a synthetic parathyroid hormone known under the name Fortero. It is used in severe cases of osteoporosis and with people at high risk for bone fractures.
With synthetic treatments, the relationship of parathyroid hormone and osteoporosis prevention becomes like that which occurs in a healthy parathyroid gland. PTH therapy has also been shown to decrease the risk of bone fracture in post-menopausal women, while increasing bone density in the areas of the spine and hip. It also appears that estrogen adds to the effects of PTH therapy. Studies have shown that PTH therapy works best in conjunction with supplemental calcium and vitamin D.
There have been some side effects associated with synthetic parathyroid hormone and osteoporosis treatment. Some patients develop muscle cramps, but these have not been reported to be chronic or long-lasting. A rise in serum calcium levels in the initial months of treatment was also noted, but there have been no reported complications resulting from the increased calcium levels.