Influence of immunoheterogeneity of circulating parathyroid hormone on results of radioimmunoassays of serum in man

Arnaud, Claude D.; Goldsmith, Ralph S.; Border, Philippe; Sizemore, Glen W.; Larsen, Judith A.; Gilkinson, Julianna

doi:10.1016/0002-9343(74)90806-7

Cited by 195 publications

(67 citation statements)

References 24 publications

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“…Our results with UcAMP expressed as micromoles per gram of creatinine are similar to the results of Arnaud et al (8) with an amino-terminal-(N-terminal) specific PTH radioimmunoassay, that is a 40% overlap with normal values. Since it is thought that N-terminal-specific PTH assays predominantly measure the serum concentrations of biologically active PTH (8), this adds 12 UcAMP ,aMOL/g CREAT.…”

Section: Resultsmentioning

confidence: 99%

Urinary cyclic AMP analyzed as a function of the serum calcium and parathyroid hormone in the idfferential diagnosis of hypercalcemia.

Shaw¹,

Oldham²,

Rosoff³

et al. 1977

J. Clin. Invest.

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A B S T R A C T Urinary cyclic AMP (UcAMP) appropriate for the serum calcium concentration was determined in normal subjects during the base-line state and during alteration in their serum calcium concentrations by saline and calcitum infusions. This was compared to the UcAMP in 76 patients with hypercalcemia and 5 patients with hypocalcemia. In 54 of 56 patients with primary hyperparathyroidism, the UcAMP was inappropriately high for their serum calcium concentration, the 2 exceptions having renal failure. In four patients with vitamin D intoxication, sarcoidosis, milkalkali syndrome, and thiazide-induced hypercalcemia and in five patients with hypocalcemia due to hypoparathyroidism, the UcAMP was appropriately low for their serum calcium concentration. In 16 patients with nonparathyroid neoplasms, 10 had UcAMP levels that were inappropriately high suggesting ectopic parathyroid hormone (PTH)-mediated hypercalcemia and 6 had UcAMP levels that were appropriately low suggesting that their hypercalcemia was due to osteolytic factors other than PTH. Correlations between UcAMP, senrm calcium concentration, and carboxyl-terminal immtunoreactive PTH suggest that random UcAMP is a sensitive accurate reflection of circulating biologically active PTH.If there is adequate renal function (serum creatinine concentration less than 2.0 mg/dl), a random UcAMP expressed as ,umol/g creatinine and analyzed as a function of the serum calcium concentration completely separates patients with PTH and non-PTHmediated hypercalcemia.

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Section: Resultsmentioning

confidence: 99%

Urinary cyclic AMP analyzed as a function of the serum calcium and parathyroid hormone in the idfferential diagnosis of hypercalcemia.

Shaw¹,

Oldham²,

Rosoff³

et al. 1977

J. Clin. Invest.

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“…Extensive use of radioimmunoassays for PTH has provided considerable insight into the role of the hormone in normal physiology and in disease states, and has also revealed the complexity of the metabolism of the hormone that results in multiple circulating molecular forms (15,16). With extensive use ofthese assays however, limitations of sensitivity have become apparent in that in many radioimmunoassay systems levels of circulating hormone in all normal individuals cannot be measured, and as a result, distinctions between normal and reduced levels are not possible.…”

Section: Discussionmentioning

confidence: 99%

“…With extensive use ofthese assays however, limitations of sensitivity have become apparent in that in many radioimmunoassay systems levels of circulating hormone in all normal individuals cannot be measured, and as a result, distinctions between normal and reduced levels are not possible. Furthermore, the elucidation of the heterogeneity of circulating hormone has indicated that fragments of reduced or absent biological activity may comprise a substantial proportion of the circulating hormone (15,16). Consequently, radioimmunoassays specific for some sequential regions of the hormone may in fact measure biologically inactive PTH.…”

Section: Discussionmentioning

confidence: 99%

Cytochemical Bioassay of Parathyroid Hormone

Goltzman¹,

Henderson²,

Loveridge³

1980

J. Clin. Invest.

143

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“…The PTH antiserum employed, GP1I, reacts primarily with determinants in the 44-68 region of the PTH molecule (26) and is par-ticularly sensitive for detection of increased parathyroid gland fuinetion (27 (29). Radioactivity in 2-ml plasma samllples was determliineI by direct scintillation counting.…”

Section: Introductionmentioning

confidence: 99%

Production, degradation, and circulating levels of 1,25-dihydroxyvitamin D in health and in chronic glucocorticoid excess.

Kumar²,

et al. 1980

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A B S T R A C T The decreasedl intestinal absorption of calcium and accelerated l)one loss associate(l with chronic glucocorticoid excess may be mediated by changes in vitamin D metabolism, leading to dlecreased availability of circulating 1,25-dihydroxyvitamin D. This hypothesis was examined in 14 patients with either endogenous or exogenous glucocorticoid excess. Analysis of paired serum samples (mean ±SE) in 13 patients duiring euglucocorticoidlisml-and dutring hyperglucocorticoidism showed that glucocorticoid excess resulted in small decreases of plasma 25-hydroxyvitamin D concentrations (22+2-18±2 ng/ml; P < 0.05) lbut no significant chaniges in plasmiia 1,25-dihydroxyvitamini D (32 ± 8-23±+46 pg/ml) or serum immunoreactive parathyroi(l hormone (21±2-18±2 ,uleq/ml). Additionally, we studied plasmna kinetics of[3H] 1 ,25-dihydroxyvitamin D3 after intravenotus bolus administration in 10 hyperglucocorticoid patients and in 14 normal controls. Assessmiient with a threecompartment model showe(d no significant abnormalities in production rates (hyperglucocorticoid patients 1.2±0.3 ,g/d, controls 1.5±0.2 ,ugld) or metabolic clearance rates (hyperglucocorticoid patients, 32 ± 3 ml/ min; controls 31+3 ml/min). Moreover, there were no significant differences in ciumulative excretion of radioactivity in urine (hyperglutcocorticoid patieints 18±2%; controls, 14±2%) or f'eces (hyperglucocorticoid patients, 60±9%, controls, 54+6%). We conclude that glucocorticoid excess does not effect plasma levels, production, or degradation of 1,25(OH)2D in hunIans. Thus, other mechanisms mutst be postulated to explain satisfactorily the abnormialities of bone structure and intestinal calciumn absorption that maiy occur after chronic glucocoi-ticoidl therapy.

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Influence of immunoheterogeneity of circulating parathyroid hormone on results of radioimmunoassays of serum in man

Cited by 195 publications

References 24 publications

Urinary cyclic AMP analyzed as a function of the serum calcium and parathyroid hormone in the idfferential diagnosis of hypercalcemia.

Urinary cyclic AMP analyzed as a function of the serum calcium and parathyroid hormone in the idfferential diagnosis of hypercalcemia.

Cytochemical Bioassay of Parathyroid Hormone

Production, degradation, and circulating levels of 1,25-dihydroxyvitamin D in health and in chronic glucocorticoid excess.

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