Plasma calcitonin

Nasal absorption. Sucrose ester of coconut fatty acid in aqueous ethanol solution (sucrose cocoate SL-40) administered intrana-sally to anesthetized male Sprague-Dawley rats at a dose of 0.5% sucrose cocoate with insulin, produced a rapid and significant increase in plasma insulin level with a concomitant decrease in blood glucose levels. Administration of a dose of 0.5% sucrose cocoate with calcitonin produced a rapid increase in plasma calcitonin levels and a concomitant decrease in plasma calcium levels . 

Gharib H, Kao PC, Heath H III. Determination of silica-purified plasma calcitonin for the detection and management of medullary thyroid carcinoma comparison of two provocative tests. Mayo Clin Proc 1987 62 373-8. 

Tisell LE, Dilley WG, Wells SA Jr. Progression of postoperative residual medullary carcinoma as monitored by plasma calcitonin levels. Surgery 1996 119 34-9. 

Wallach SR, Royston I, Taetle R, Wohl H, Deftos LJ, Plasma calcitonin as a marker of disease activity in patients with small cell carcinoma of the lung. J Chn Endocrinol Metab 1981 53 602-6. 

Calcitonin Neither deficiency nor excess of calcitonin is known to have any pathological effects. Plasma calcitonin is increased in the medullary carcinoma of the thyroid. Binds to cell-surface receptors in bone and kidney, increasing intracellular cAMP may also function by activation of phospholipase C signal transduction pathway, decreases Ca " " release from bone and stimulate Ca " " and phosphate excretion in kidneys, generally antagonistic to PTH. 

Shimatani T, Inoue M, Kuroiwa T, Xu J, Nakamura M, Tazuma S, Ikawa K, Morikawa N. Lafutidine, a newly developed antiulcer drug, elevates postprandial intragastric pH and increases plasma calcitonin gene-related peptide and somatostatin concentrations in humans comparisons with famotidine. Dig Dis Sd 2006 51 114-20. 

The patient was placed on an essentially purine-free diet and received no medication for 5 days. Uric acid metabolism disclosed uricemia 2.0 mg/dl uricosuria 510 mg/day Cur 15.4 ml/min Ccr 91 ml/min fractional excretion of uric acid (Cur/Ccr) 16.9%. Basal plasma calcitonin was 168 pg/ml (normal values undetectable). A pentagastrin bolus injection of 0.5 g/Kg elevated plasma calcitonin over 1000 pg/ml. Simultaneously, serum uric acid decreased from 2.0 mg/dl to 1.3 mg/dl, and Cur/Ccr increased from 16.9% to 25.7%. A pentagastrin test in two control subjects did not make plasma calcitonin levels detectable, nor did it modify uric acid excretion. Her clinical course was progressively down-hill and she died after several bronchoneumonic episodes and massive tracheal hemorrage. Pyrazinamide and probenecid tests could not be done. Permission for autopsy was denied. 

Our patient had basal hypouricemia due to renal urate overexcretion. Renal leak of other substances and inappropriate secretion of ADH were ruled out. Pentagastrin injection elevated plasma calcitonin with simultaneous increment of urate fractional excretion and diminution of serum uric acid, lending support to the hypothesis... 

The secretion of calcitonin, like that of PTH, is probably governed solely by blood calcium concentration, since there is no evidence for the existence of a trophic hormone that stimulates its release. The dual control system represented by PTH and calcitonin exerts rigorous control over the plasma calcium concentration and is much more efficient than PTH would be acting alone. Calcitonin is somewhat quicker acting than PTH and may be involved in rapid adjustments when the plasma calcium concentration might otherwise overshoot . It has been suggested that while PTH is really the main regulator for plasma, calcitonin is somehow concerned with the balance between bone formation and resorption. 

Calcitonin is secreted when abnormally high calcium levels occur in plasma. Although plasma concentrations are normally minute (<100 pg/mL), they increase two- to threefold after calcium infusion. Calcitonin has a short plasma half-life (ca 10 min). Certain thyroid tumors are the result of CT concentrations 50—500 times normal. The mechanism of action is a direct inhibition of bone resorption. Calcitonin is used clinically in various diseases in which hypercalcemia is present, eg, Paget s disease (46). 

Calcitonin. Calcitonin is available commercially from pork and salmon extracts (Calcimar, Armour) as well as by synthesis. Preparations are bioassayed on the basis of their calcium-lowering activity in comparison to the potency of pure pork calcitonin of which ca 4 p.g is equivalent to 1 MRC unit (Medical Research Council, U.K.). For clinical use, vials containing 400 units in 4 mL are available. The recommended daily dosage is 100 units to be adrninistered subcutaneously or intramuscularly because its plasma half-life is short (4—12 min). 

Vitamin D withdrawal is an obvious treatment for D toxicity (219). However, because of the 5—7 d half-life of plasma vitamin D and 20—30 d half-life of 25-hydroxy vitamin D, it may not be immediately successful. A prompt reduction in dietary calcium is also indicated to reduce hypercalcemia. Sodium phytate can aid in reducing intestinal calcium transport. Calcitonin glucagon and glucocorticoid therapy have also been reported to reduce semm calcium resulting from D intoxication (210). 

Three hormones regulate turnover of calcium in the body (22). 1,25-Dihydroxycholecalciferol is a steroid derivative made by the combined action of the skin, Hver, and kidneys, or furnished by dietary factors with vitamin D activity. The apparent action of this compound is to promote the transcription of genes for proteins that faciUtate transport of calcium and phosphate ions through the plasma membrane. Parathormone (PTH) is a polypeptide hormone secreted by the parathyroid gland, in response to a fall in extracellular Ca(Il). It acts on bones and kidneys in concert with 1,25-dihydroxycholecalciferol to stimulate resorption of bone and reabsorption of calcium from the glomerular filtrate. Calcitonin, the third hormone, is a polypeptide secreted by the thyroid gland in response to a rise in blood Ca(Il) concentration. Its production leads to an increase in bone deposition, increased loss of calcium and phosphate in the urine, and inhibition of the synthesis of 1,25-dihydroxycholecalciferol. 

Sizemore, G. W. Heath, H. Ill "Immunochemical Heterogeneity of Calcitonin in Plasma of Patients With Medullary Carcinoma of the Thyroid". J. Clin. Invest. (1975), In Press. 

More than 99% of total body calcium is found in bone the remaining less than 1% is in the ECF and ICE Calcium plays a critical role in the transmission of nerve impulses, skeletal muscle contraction, myocardial contractions, maintenance of normal cellular permeability, and the formation of bones and teeth. There is a reciprocal relationship between the serum calcium concentration (normally 8.6 to 10.2 mg/dL [2.15 to 2.55 mmol/L]) and the serum phosphate concentration that is regulated by a complex interaction between parathyroid hormone, vitamin D, and calcitonin. About one-half of the serum calcium is bound to plasma proteins the other half is free ionized calcium. Given that the serum calcium has significant protein binding, the serum calcium concentration must be corrected in patients who have low albumin concentrations (the major serum protein). The most commonly used formula adds 0.8 mg/dL (0.2 mmol/L) of calcium for each gram of albumin deficiency as follows ... 

T8. Tidgren, B., Theodorsson, E., and Hjemdahl, P, Renal and systemic plasma immunoreactive neuropeptide Y and calcitonin gene-related peptide responses to mental stress and adrenaline in humans. Clin.Physioi. 11,9-19 (1991). 

The release of calcitonin from the thyroid is regulated by plasma calcium levels through negative feedback. An increase in the level of calcium in the... 

The benzyl ester of hyaluronic acid (HYAFF 11) is a highly mucoadhesive polymer which can be processed into microspheres. Such microspheres containing salmon calcitonin were intravaginally administered to rats as a dosage form for the prevention of ovariectomy osteopenia [65]. In recent studies, HYAFF 11-salmon calcitonin microspheres were formulated as single-dose pessaries, resulting in sustained plasma concentrations of calcitonin [67]. 

Calcitonin a peptide hormone secreted by the thyroid gland that lowers plasma calcium levels by increasing the deposition of bone. 

The polypeptide calcitonin is secreted by thyroid C-cells during imminent hypercalcemia. It lowers plasma Ca + levels by inhibiting osteoclast activity. Its uses include hypercalcemia and osteoporosis. Remarkably, calcitonin injection may produce a sustained analgesic effect that is not restricted to bone pain. 

Calcitonin, a peptide produced in the C cells of the thyroid gland, inhibits the resorption of both calcium and phosphate ions. The result is an overall reduction in the plasma level of both ions. Calcitonin is thus a parathyrin antagonist relative to Ca ". ... 

Calcitriol and parathyroid hormone, on the one hand, and calcitonin on the other, ensure a more or less constant level of Ca "" in the blood plasma and in the extracellular space (80-110 mg 2.0-2.6 mM). The peptide parathyroid hormone (PTH 84 AA) and the steroid calcitriol (see p. 374) promote direct or indirect processes that raise the Ca "" level in blood. Calcitriol increases Ca "" resorption in the intestines and kidneys by inducing transporters. Parathyroid hormone supports these processes by stimulating calcitriol biosynthesis in the kidneys (see p. 330). In addition, it directly promotes resorption of Ca "" in the kidneys (see p. 328) and Ca "" release from bone (see B). The PTH antagonist calcitonin (32 AA) counteracts these processes. 

Calcium is the principal extracellular electrolyte regulated by PTH, calcitonin, and D3. Extracellular calcium is a critical component of signal transduction across the plasma membrane, which regulates a wide spectrum of physiological events including muscle contraction, secretion of neurotransmitters and hormones, and the ac-... 

Hypocalcemia directly increases PTH synthesis and release and inhibits calcitonin release. PTH in turn restores plasma calcium by initially stimulating transport of free or labile calcium from bone into the blood. PTH also increases renal 1,25-dihydroxycholecalciferol (1,25-(0H)2D3) production, which is the most active form of D3. 1,25-(0H)2D3 induces enterocyte differentiation in the intestine, which in turn results in increased absorption of calcium. Finally, during long periods of hypocalcemia, PTH can mobilize more stable calcium deep in the hydroxyapatite of bone by activating deep osteoclasts. 

Plasma calcium level is precisely regulated by three hormones e.g. parathormone, calcitonin and calciferol (which is a active form of vitamin D). They control its absorption, exchange with bone and excretion. 

Calcium is present in three forms e.g., as free calcium ion, bound to plasma protein albumin and in diffusable complexes. The endocrine system, through parathyroid hormone and calcitonin, helps in keeping the concentration of ionized plasma calcium in normal level. Decrease in plasma levels of ionized calcium leads to increased parathyroid hormone secretion. Parathyroid hormone tends to increase plasma calcium level by increasing bone resorption, increasing intestinal absorption and increasing reabsorption of calcium in kidney. Vitamin D acts by stimulating... 

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