Thyrocalcitonin

A hormone, the only known secretory product of the parenchymal or C cells of the mammalian thyroid and of the ultimobranchial glands of lower forms.

In conjunction with the parathyroid hormone, thyrocalcitonin is of prime importance in regulating calcium and phosphate metabolism. Its major function is to protect the organism from the dangerous consequences of elevated blood calcium. Its sole known effect is that of inhibiting the resorption of bone. It thus produces a fall in the concentration of calcium and phosphate in the blood plasma because these two minerals are the major constituents of bone mineral and are released into the bloodstream in ionic form when bone is resorbed. See Bone, Parathyroid gland, Parathyroid hormone

Thyrocalcitonin also causes an increased excretion of phosphate in the urine under certain circumstances, but a question remains as to whether this is a direct effect of the hormone upon the kidney or an indirect consequence of the fall in blood calcium which occurs when the hormone inhibits bone resorption. See Thyroid gland

Thyrocalcitonin

(calcitonin), a hormone in vertebrate animals and man that decreases the Ca²⁺ content in the blood plasma. In fishes, amphibians, reptiles, and birds, thyrocalcitonin is secreted by the ultimobranchial bodies, which develop from the last pair of branchial arches. In mammals, this tissue is represented by the C cells of the interfollicular islets of the thyroid gland.

Thyrocalcitonin, which can be isolated from the thyroid glands of swine and man, is a polypeptide containing 32 amino-acid residues. By constantly inhibiting the resorption of Ca²⁺ from the bones, it promotes homeostasis and the growth of bone tissue. This is important where there is an increased need for Ca²⁺, such as periods of bone growth in young animals, pregnancy and lactation in mammals, and egg laying in birds. Thyrocalcitonin also increases the excretion of phosphates in the urine. It regulates the content of Ca²⁺ and phosphates in the body by interaction with the parathyroid hormone, which stimulates the release of Ca²⁺ from bone tissue into the extracellular fluid.

REFERENCES

Aleshin, B. V. “Novye dannye o tireokal’tsitonine.” Uspekhi sovremennoi biologii, 1970, vol. 69, issue 1.
Sovremennye voprosy endokrinologii, fasc. 4. Moscow, 1972. (Collection of articles.)
“Symposium on Thyrocalcitonin.” American Journal of Medicine, 1967, vol. 43, no. 5.
Hirsch, P. F., and P. L. Munson. “Thyrocalcitonin.” Physiological Reviews, 1969, vol. 49. no. 3.

L. V. KRIUKOVA

thyrocalcitonin

[¦thī·rō‚kal·sə′tō·nən] (biochemistry) calcitonin

thyrocele

goiter

[goi´ter] enlargement of the thyroid gland" >thyroid gland, causing a swelling in the front part of the neck; called also struma. adj., adj goit´rous. If there is evidence of pressure against the throat, or the possibility of a malignancy, the goiter may be removed surgically. Simple endemic goiter is usually caused by lack of iodine in the diet. In graves' disease, goiter is accompanied by excessive thyroid hormones in the blood and symptoms of hyperthyroidism.aberrant goiter goiter of a supernumerary thyroid gland.adenomatous goiter that caused by adenoma or multiple colloid nodules of the thyroid gland.Basedow goiter a goiter" >colloid goiter that has become hyperfunctioning after administration of iodine.colloid goiter one that is large and soft and has distended spaces filled with colloid.cystic goiter one with cysts formed by mucoid or colloid degeneration.diffuse toxic goiter exophthalmic goiter.endemic goiter goiter occurring widely in a geographic region where the food or water is deficient in iodine. Treatment consists of iodine replacement; although this will not cure the condition, it can stop it from enlarging, and iodine administered in advance will prevent development of goiter.exophthalmic goiter any type accompanied by exophthalmos.fibrous goiter goiter in which the thyroid capsule and stroma are hyperplastic.follicular goiter parenchymatous goiter.intrathoracic goiter one with part of the enlarged gland in the thoracic cavity.iodide goiter that occurring in reaction to iodides at high concentrations, due to inhibition of iodide organification.multinodular goiter one with circumscribed nodules within the gland.nontoxic goiter that occurring sporadically and not associated with hyperthyroidism or hypothyroidism.parenchymatous goiter one with increase in follicles and proliferation of epithelium.perivascular goiter one that surrounds a large blood vessel.retrovascular goiter one with processes behind a large blood vessel.substernal goiter one whose lower part lies beneath the sternum.suffocative goiter one that causes dyspnea due to pressure.toxic multinodular goiter hyperthyroidism arising in a goiter" >multinodular goiter, usually of long standing.vascular goiter one due chiefly to dilatation of the blood vessels of the thyroid gland.

thy·ro·cele

(thī'rō-sēl), A tumor of the thyroid gland, such as a goiter. [thyro- + G. kēlē, tumor]

thyrocele

An older, nonspecific term defined as either:
(1) A thyroid tumour; or
(2) A thyroid enlargement—e.g., goitre or thyromegaly.

thy·ro·cele

(thī'rō-sēl) A tumor of the thyroid gland, such as a goiter. [thyro- + G. kēlē, tumor]

thy·ro·cele

(thī'rō-sēl) Tumor of thyroid gland, such as goiter. [thyro- + G. kēlē, tumor]

单词	thyrocele
释义	DictionarySeegoiter Thyrocalcitonin Thyrocalcitonin A hormone, the only known secretory product of the parenchymal or C cells of the mammalian thyroid and of the ultimobranchial glands of lower forms. In conjunction with the parathyroid hormone, thyrocalcitonin is of prime importance in regulating calcium and phosphate metabolism. Its major function is to protect the organism from the dangerous consequences of elevated blood calcium. Its sole known effect is that of inhibiting the resorption of bone. It thus produces a fall in the concentration of calcium and phosphate in the blood plasma because these two minerals are the major constituents of bone mineral and are released into the bloodstream in ionic form when bone is resorbed. See Bone, Parathyroid gland, Parathyroid hormone Thyrocalcitonin also causes an increased excretion of phosphate in the urine under certain circumstances, but a question remains as to whether this is a direct effect of the hormone upon the kidney or an indirect consequence of the fall in blood calcium which occurs when the hormone inhibits bone resorption. See Thyroid gland Thyrocalcitonin (calcitonin), a hormone in vertebrate animals and man that decreases the Ca²⁺ content in the blood plasma. In fishes, amphibians, reptiles, and birds, thyrocalcitonin is secreted by the ultimobranchial bodies, which develop from the last pair of branchial arches. In mammals, this tissue is represented by the C cells of the interfollicular islets of the thyroid gland. Thyrocalcitonin, which can be isolated from the thyroid glands of swine and man, is a polypeptide containing 32 amino-acid residues. By constantly inhibiting the resorption of Ca²⁺ from the bones, it promotes homeostasis and the growth of bone tissue. This is important where there is an increased need for Ca²⁺, such as periods of bone growth in young animals, pregnancy and lactation in mammals, and egg laying in birds. Thyrocalcitonin also increases the excretion of phosphates in the urine. It regulates the content of Ca²⁺ and phosphates in the body by interaction with the parathyroid hormone, which stimulates the release of Ca²⁺ from bone tissue into the extracellular fluid. REFERENCES Aleshin, B. V. “Novye dannye o tireokal’tsitonine.” Uspekhi sovremennoi biologii, 1970, vol. 69, issue 1. Sovremennye voprosy endokrinologii, fasc. 4. Moscow, 1972. (Collection of articles.) “Symposium on Thyrocalcitonin.” American Journal of Medicine, 1967, vol. 43, no. 5. Hirsch, P. F., and P. L. Munson. “Thyrocalcitonin.” Physiological Reviews, 1969, vol. 49. no. 3. L. V. KRIUKOVA thyrocalcitonin [¦thī·rō‚kal·sə′tō·nən] (biochemistry) calcitonin thyrocele goiter [goi´ter] enlargement of the thyroid gland" >thyroid gland, causing a swelling in the front part of the neck; called also struma. adj., adj goit´rous. If there is evidence of pressure against the throat, or the possibility of a malignancy, the goiter may be removed surgically. Simple endemic goiter is usually caused by lack of iodine in the diet. In graves' disease, goiter is accompanied by excessive thyroid hormones in the blood and symptoms of hyperthyroidism.aberrant goiter goiter of a supernumerary thyroid gland.adenomatous goiter that caused by adenoma or multiple colloid nodules of the thyroid gland.Basedow goiter a goiter" >colloid goiter that has become hyperfunctioning after administration of iodine.colloid goiter one that is large and soft and has distended spaces filled with colloid.cystic goiter one with cysts formed by mucoid or colloid degeneration.diffuse toxic goiter exophthalmic goiter.endemic goiter goiter occurring widely in a geographic region where the food or water is deficient in iodine. Treatment consists of iodine replacement; although this will not cure the condition, it can stop it from enlarging, and iodine administered in advance will prevent development of goiter.exophthalmic goiter any type accompanied by exophthalmos.fibrous goiter goiter in which the thyroid capsule and stroma are hyperplastic.follicular goiter parenchymatous goiter.intrathoracic goiter one with part of the enlarged gland in the thoracic cavity.iodide goiter that occurring in reaction to iodides at high concentrations, due to inhibition of iodide organification.multinodular goiter one with circumscribed nodules within the gland.nontoxic goiter that occurring sporadically and not associated with hyperthyroidism or hypothyroidism.parenchymatous goiter one with increase in follicles and proliferation of epithelium.perivascular goiter one that surrounds a large blood vessel.retrovascular goiter one with processes behind a large blood vessel.substernal goiter one whose lower part lies beneath the sternum.suffocative goiter one that causes dyspnea due to pressure.toxic multinodular goiter hyperthyroidism arising in a goiter" >multinodular goiter, usually of long standing.vascular goiter one due chiefly to dilatation of the blood vessels of the thyroid gland. thy·ro·cele (thī'rō-sēl), A tumor of the thyroid gland, such as a goiter. [thyro- + G. kēlē, tumor] thyrocele An older, nonspecific term defined as either: (1) A thyroid tumour; or (2) A thyroid enlargement—e.g., goitre or thyromegaly. thy·ro·cele (thī'rō-sēl) A tumor of the thyroid gland, such as a goiter. [thyro- + G. kēlē, tumor] thy·ro·cele (thī'rō-sēl) Tumor of thyroid gland, such as goiter. [thyro- + G. kēlē, tumor]
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