Parathyroidin, also known as parathyroid hormone or PTH, is a hormone secreted by the parathyroid glands. It plays a crucial role in regulating calcium and phosphorus levels in the body.
Parathyroidin acts primarily on the bones, kidneys, and intestines to maintain the balance of calcium in the blood. It stimulates the release of calcium from bones, which increases the concentration of calcium in the blood when levels are low. This process is known as bone resorption. Additionally, parathyroidin enhances the reabsorption of calcium in the kidneys, preventing its excretion in the urine. It also promotes the conversion of vitamin D into its active form, which aids in the absorption of calcium from the intestines.
The release of parathyroidin is controlled by the level of calcium in the blood. When calcium levels drop, the parathyroid glands are stimulated to produce and release more parathyroidin, which acts to raise calcium levels back to normal. Conversely, when calcium levels are high, the production and release of parathyroidin are inhibited, thus preventing excessively elevated calcium levels.
Imbalances in parathyroidin levels can result in various disorders, such as hyperparathyroidism (excessive production of parathyroidin) or hypoparathyroidism (inadequate production of the hormone). These conditions can lead to abnormal calcium and phosphorus levels in the blood, causing symptoms like bone pain, kidney stones, muscle weakness, and fatigue.
In summary, parathyroidin is a hormone produced by the parathyroid glands that regulates calcium and phosphorus levels in the body through its action on the bones, kidneys, and intestines.
