Description of the medicine: Calcitonin (Calcitonin)
The hypocalcemic hormone produced by the parafollicular bright cells of the thyroid gland and similar cells of the thymus and parathyroid glands of mammals, animals, and humans.
By chemical nature, calcitonin is a polypeptide consisting of 32 amino acid residues; molecular weight 3600 - 4000.
Currently, 8 types of calcitonin are known, of which salmon, pig and human calcitonin are of medical value. Synthetic methods for producing calcitonin have been developed.
The activity of the drug is expressed in units of action (ED) or international units (IU) and is determined by the biological or radioimmunological method. When determined by a biological method, the amount of hormone that causes rats (under certain experimental conditions) to reduce blood calcium by 10% is taken as 1 unit. 1 IU corresponds to 0.2 μg of pure peptide (synthetic salmon calcitonin).
Abroad, natural and synthetic calcitonin preparations are available under the names: Calcimar, Calcitar, Calcitonin, Caldcalcin, Calirsan, Calsynar, Cibacalcin, Elcatonin, Miacalcic, Miacalcin, Salcatonin, Thyrocalcitonin, etc.
In our country, an injectable dosage form of calcitonin from the thyroid gland of pigs called "Calcitrin" has been developed.
Calcitonin is constantly present in the blood. Its concentration increases with meals rich in calcium salts.
The physiological role of calcitonin is determined by participation in the regulation of calcium and phosphate metabolism in the body; its action is carried out with the participation of parathyroid hormone and the activation of the form of vitamin D (see Ergocalciferol).
Calcitonin significantly reduces the yield of calcium from bones in conditions that are associated with a sharply increased rate of bone resorption and bone formation, such as Paget's disease, malignant osteolysis, and some forms of osteoporosis characterized by a high level of mineral metabolism. The drug inhibits the activity of osteoclasts and stimulates the formation and activity of osteoblasts; inhibits osteolysis, reducing the increased content of calcium in blood serum. In addition, it enhances the excretion of calcium, phosphorus and sodium in the urine by reducing their reabsorption in the renal tubules. However, the concentration of calcium in serum does not fall below normal values.
Calcitonin also reduces gastric secretion and exocrine pancreatic secretion, without affecting the motility of the gastrointestinal tract. Clinical studies show that the drug has an analgesic effect.