Intact parathyroid hormone

TABLE 23-4. Target Levels for Calcium, Phosphorus, Calcium-Phosphorus Product, and Intact Parathyroid Hormone... 

Brown RC, Aston JP,Weeks I, et al. Circulation intact parathyroid hormone measured by a two-site immunochemilumino-tetric assay. /. Clin. Endocrinol. Metab. (1987) 65 407-414. 

A non-(l-84) circulating parathyroid hormone (PTH) fragment interferes significantly with intact PTH commercial assay measurements in uremic samples. Clin. Chem. (1998) 44 805-809. 

The major function of the parathyroid hormone (PTH parathormone) is to regulate the concentration of extracellular calcium. PTH is heterogeneous and circulates as an intact polypeptide and as fragments. The major circulating biologically active peptide is intact PTH, which is rapidly cleared from the circulation (half-life less than 10 min). The N-terminal portion is responsible for its biologic activity. 

A 31-year-old woman developed diffuse musculoskeletal pain. She had been taking calcium and dihydrota-chysterol up to 4 mg/day for 6 months for hypoparathyroidism after subtotal thyroid resection. She had severe hypercalcemia (4.1 mmol/1), no detectable intact parathyroid hormone, renal insufficiency (serum creatinine 486 pmol/l), and a normochromic anemia (6.6 g/dl). Rehydration and forced diuresis initially improved renal function and reduced the serum calcium concentration, but the calcium concentration after 4 weeks was still 3.0 mmol/1 and it did not normalize until she was given a single intravenous dose of pamidronate 15 mg. 

Martin KJ, Gonzalez EA, GeUens M, Hamm LL, Abboud H, Lindberg J. 19-Nor-l-alpha-25-dihydroxyvitamin D2 (Paricalcitol) safely and effectively reduces the levels of intact parathyroid hormone in patients on hemodialysis. J Am Soc Nephrol 1998 9 1427-32. 

Figure 49-8 Diurnal variation of serum phosphate in men (O) and women ( ). Meals and snacks are indicated by arrows the bar indicates recumbent posture. (From Calvo MS, Eastell R, Offord KP, Bergstralh EJ, Burritt ME. Circadian variation in ionized calcium and intact parathyroid hormone evidence for gender differences in calcium homeostasis.] Clin Endocrinol Metab 1991 72 69-76, The Endocrine Society.)...

Figure 49-10 Amino acid sequence of preproparathyroid hormone. Arrows indicate the sites of cleavage by proteases to remove the N-terminal methionines (/), the leader (pre) sequence (2), and the pro sequence (3), producing intact PTH (1-84). Cleavage at position 4 produces inactive carboxyl (C)-terminai fragments. (From Habener JF, Rosenblatt Ni, Potts JT Jr. Parathyroid hormone Biochemical aspects of biosynthesis, secretion, action, and metabolism. Physiol Rev 1984 64 985-1053.)...

Figure 49-12 Secretion, metabolism, clearance, and circulating forms of PTH. Both intact PTH and inactive fragments containing the middle and carboxyl (C)-terminal amino acids are secreted by the parathyroid glands.These inactive fragments are also produced by peripheral metabolism of intact PTH by the liver and kidneys. Carboxyl fragments are cleared by the kidneys by glomerular filtration.The half-life and concentration of intact hormone are small compared with those of inactive fragments. (From Endres DB, Villanueva R, Sharp CF jr. Singer FR. Measurement of parathyroid hormone. Endocrinol Metab Clin North Am 1989 18 611-29.)...

Figure 49-16 Intact PTH in assessing parathyroid function in end-stage renal disease. Dialysis patients were separated into those with early and advanced osteitis fibrosa, osteomalacia, and aplastic disease by quantitative histomorphometric analysis of undecalcified bone biopsies. (From Segre GV, Sherrard DJ, Pandian /WR, et al. Intact PTH (IRMA) II New applications to issues in parathyroid hormone and mineral metabolism. San Juan Capistrano, Calif Nichols Institute, 1989.)...

Brossard J-H, Cloutier M, Roy L, Lepage R, Gascon-Barre M, D Amour P. Accumulation of a non-(l-84) molecular form of parathyroid hormone (PTH) detected by intact PTH assay in renal failure importance in the interpretation of PTH values. J Cfin Endocrinol Metab 1996 81 3923-9. 

Brown RC, Aston JP, St John A, Woodhead JS. Comparison of poly- and monoclonal antibodies as labels in a two-site immunochemduminometric assay for intact parathyroid hormone. J Immunol Methods 1988 109 139-44. 

Brown RC, Aston JP, Weeks I, Woodhead JS. Circulating intact parathyroid hormone measured with a two-site immunochemiluminometric assay. J Clin Endocrinol Metab 1987 65 407-14. 

Calvo MS, Eastell R, Offord KP, Bergstralh EJ, Burritt MF. Circadian variation in ionized calcium and intact parathyroid hormone evidence for sex differences in calcium homeostasis. J Cfin Endocrinol Metab 1991 72 69-76. 

Moriniere P> Gueris J> et al. Comparison of intact, midregion, and carboxy terminal assays of parathyroid hormone for the diagnosis of bone disease in hemodialysed patients. J Clin Endocrinol Metab 1991 73 516-24. ... 

Curley IR, Wheeler MH, Aston JP, Brown RC, Weeks I, Woodhead JS. Studies in patients with hyperparathyroidism using a two-site immunochemilumi-nometric assay for circulating intact (1-84) parathyroid hormone. Surgery 1987 102 926-31. 

Daugaard H, Eg ord M, Olgaard K. Influence of calcium on the metabolism of intact parathyroid hormone by isolated perfused rat kidney and Ever. Endocrinology 1990 126 1813-20. 

Davis OK, Hawkins DS, Rubin LP, Posillico JT, Brown EM, Schiff I. Serum parathyroid hormone in pregnant women determined by an immunoradiometric assay for intact PTH. J Clin Endocrinol Metab 1988 67 850-2. 

Fraser WD, Logue FC, MacRitchie K, Wilson RM, Gray HW, Beastall GH, et al. Intact parathyroid hormone concentration and cyclic AMP metabolism in thyroid disease. Acta Endocrinol 1991 124 652-7. 

Frolich M, Wahna ST, Paulson C> Papapoulos SE. Immunoradiometric assay for intact human parathyroid hormone characteristics, clinical appHcation and comparison with a radioimmunoassay. Ann Clin Biochem 1990 27 69-72. 

Kitamura N> Shigeno C, Shiomi K, Lee K, Ohta S, Sone T, et al. Episodic fluctuation in serum intact parathyroid hormone concentration in men. J Clin Endocrinol Metab 1990 70 252-63. 

Malini S. Lithium treatment increases intact and midregion parathyroid hormone and parathyroid volume. J Clin Endocrinol Metab 1989 68 654-60. 

Newman DJ, Ashby JP. Clinical and laboratory evaluation of a two-site immunoradiometric assay for intact parathyroid hormone. Ann Clin Biochem 1988 25 654-60. 

Papantoniou NE, Papapetrou PD, AntsakUs AJ, Kon-toleon PE, Mesogitis SA, Aravantinos D. Circulating levels of immunoreactive parathyroid hormone-related protein and intact parathyroid hormone in human fetuses and newborns. Eur J Endocrinol 1996 134 437-42. 

Koivula T. Intact parathyroid hormone, ionized calcium and calcium infusion test in the evaluation of hyperparathyroidism in chronic renal failure. 

Rubin LP, Posillico JT, Anast CS, Brown EW. Circulating levels of biologically active and immunoreactive intact parathyroid hormone in human newborns. Pediatr Res 1991 29 201-7. 

Saggese G, BaronceUi GI, Bertelloni S, CipoUoni C. Intact parathyroid hormone levels during pregnancy in healthy term neonates and in hypocalcemic preterm infants. Acta Paediatr Scand 1991 80 36-41. 

Segre GV, Sherrard DJ, Pandian MR, et al. Intact PTH (IRMA) II new applications to issues in parathyroid hormone and mineral metabolism. Nichols Institute, San Juan Capistrano, Calif, 1989. 

Wang M, Hercz G, Sherrard DJ, Maloney NA, Maloney NA, Segre GV, et al. Relationship between intact 1-84 parathyroid hormone and bone histomor-phometric parameters in dialysis patients without aluminum toxicity. Am J Kidney Dis 1995 26 836-44. 

Hypocalcemic perfusion of the pig thyroid in situ results in a slight rise in the systemic blood calcium level, which might be caused by a shutting-off of thyrocalcitonin secretion (C5). The normal level of thyrocalcitonin output might depend on the prevailing level of secretion of parathyroid hormone this possibility is supported by the observation that hypocalcemic perfusion of the thyroid in parathyroidectomized pigs was unaccompanied by the rise in systemic plasma calcium observed in intact animals. Until sensitive immunoassay procedures become more widely available, however, it is difficult to be sure whether or not thyrocalcitonin is secreted under resting conditions in the intact animal. A preliminary report of a radioimmunoassay technique for thyrocalcitonin, by Arnaud and Littledyke (A5), indicates that all plasma samples examined contained detectable thyrocalcitonin, and that thyroidectomy resulted in a decrease in thyrocalcitonin levels below those found in normal animals. 

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