What Is the Connection Between Parathyroid Hormone and Calcitonin?
Basic single-chain polypeptide hormone secreted by parathyroid gland cells. Referred to as PTH. Parathyroid hormone is composed of 84 amino acids. Its main function is to regulate the metabolism of calcium and phosphorus in vertebrates, which promotes the increase of blood calcium levels and the decrease of blood phosphorus levels.
Precursor of parathyroid hormone
- TCM disease name
- Precursor of parathyroid hormone
- English name
- Parathyroid hormone precursor
- Visiting department
- Endocrinology
- Common causes
- Abnormal parathyroid hormone secretion
- Common symptoms
- Osteoporosis, hypercalcemia
- Basic single-chain polypeptide hormone secreted by parathyroid gland cells. Referred to as PTH. Parathyroid hormone is composed of 84 amino acids. Its main function is to regulate the metabolism of calcium and phosphorus in vertebrates, which promotes the increase of blood calcium levels and the decrease of blood phosphorus levels.
- Basic single-chain polypeptide hormone secreted by parathyroid gland cells. Referred to as PTH. Parathyroid hormone is composed of 84 amino acids. Its main function is to regulate the metabolism of calcium and phosphorus in vertebrates, which promotes the increase of blood calcium levels and the decrease of blood phosphorus levels. The first precursor substance of PTH is first synthesized in the main cells of the parathyroid gland, called proprothyroid hormone, containing 115 amino acids. Later, this precursor substance is cleaved into a second precursor substance containing 90 amino acids in the form of a parathyroid hormone. Paraprohormone, which in turn is cleaved into a peptide containing 84 amino acids in the cell, PTH. The concentration of PTH in normal human plasma is about 1 ng / ml.
- The half-life of PTH in circulating blood is about 20 minutes, and it is mainly inactivated in the kidney. Although the body's calcium metabolism is affected by a variety of hormones, the two main hormones that regulate the concentration of calcium in extracellular fluid are PTH and calcitonin secreted by parathyroid follicular cells. In addition, PTH indirectly promotes intestinal absorption of Ca2 +. The direct effect of PTH on the kidney is to promote the reabsorption of Ca2 + by the renal tubules, thereby reducing the excretion of Ca2 + from the urine. PTH indirectly increases intestinal Ca2 + absorption by activating vitamin D3. PTH secretion is mainly regulated by plasma Ca2 + concentration. If the secretion of PTH is too vigorous, the balance between bone formation and bone erosion is destroyed, and the enhanced osteoclast activity is dominant. In the long term, it will cause the erosion of bone calcium, which is prone to fracture or bone deformity. Too high and cause a series of bad results. If the secretion of PTH is insufficient, the excretion of phosphate by the kidneys is reduced and calcium phosphate is deposited in the bone. Another important hormone that regulates calcium metabolism in the body is calcitonin, which is a peptide hormone secreted by cells near the thyroid follicles. Calcitonin can reduce blood calcium levels.
- Increased: primary hyperparathyroidism, ectopic hyperparathyroidism, hyperparathyroidism secondary to kidney disease, pseudohypoparathyroidism.
Reduction: Hypoparathyroidism due to thyroidectomy, renal failure and non-parathyroid hypercalcemia due to hyperthyroidism.
- Radioimmunoassay: Amino terminal (active terminal) 230 630ng / L; carboxy terminal (inactive terminal) 430 1860ng / L.
Immunochemical fluorescence method: 1 10pmol / L.