The Acute Parathyroid Hormone Response to Changes in Ionized Calcium during Phosphate Infusions in the Cow

We examined the effect of aging on the relationship between the concentrations of blood ionized calcium and of serum parathyroid hormone (PTH) in 22 healthy men [9 elderly (age 74 +/- 2 yr) and 13 young (age 39 +/- 1 yr)] in whom the glomerular filtration rate was > 70 ml/min. Throughout a 24-h period, serum concentrations of PTH in the elderly men were twice those in the young men, whereas blood ionized calcium did not differ between the two groups. With intravenous infusion of calcium gluconate, the minimum PTH concentration was two- to threefold higher in the elderly men. With infusion of NaEDTA. the maximum PTH concentration was 20% higher in the elderly men. The calcium set point for PTH release was higher in the elderly than in the young men (4.71 +/- 0.04 vs. 4.54 +/- 0.03 mg/dl, respectively, P < 0.005). In these healthy men, the age-related increase in serum PTH could not be attributed to a sustained decrease in concentration of either blood ionized calcium or 1,25-hydroxyvitamin D. These findings suggest that, with aging, the relationship between calcium and PTH is altered such that at any given level of calcium, the concentration of PTH is higher.

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Altered diurnal regulation of blood ionized calcium and serum parathyroid hormone concentrations during parenteral nutrition

American Journal of Clinical Nutrition ◽

10.1093/ajcn/71.2.560 ◽

2000 ◽

Vol 71 (2) ◽

pp. 560-568 ◽

Cited By ~ 14

Author(s):

William G Goodman ◽

Sudipta Misra ◽

Johannes D Veldhuis ◽

Anthony A Portale ◽

He-Jing Wang ◽

...

Keyword(s):

Parathyroid Hormone ◽

Parenteral Nutrition ◽

Ionized Calcium ◽

Serum Parathyroid Hormone ◽

Diurnal Regulation

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Response to an oral calcium load in nephrolithiasis patients with fluctuating parathyroid hormone and ionized calcium levels

Brazilian Journal of Medical and Biological Research ◽

10.1590/s0100-879x2004000900013 ◽

2004 ◽

Vol 37 (9) ◽

pp. 1379-1388 ◽

Cited By ~ 4

Author(s):

S.A. Gomes ◽

A. Lage ◽

M. Lazaretti-Castro ◽

J.G.H. Vieira ◽

I.P. Heilberg

Keyword(s):

Parathyroid Hormone ◽

Ionized Calcium ◽

Oral Calcium ◽

Calcium Load

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The cardiovascular system in patients with symptomatic and mild primary hyperparathyroidism

Problems of Endocrinology ◽

10.14341/probl200955325-29 ◽

2009 ◽

Vol 55 (3) ◽

pp. 25-29 ◽

Cited By ~ 1

Author(s):

I V Voronenko ◽

N G Mokrysheva ◽

L Ya Rozhinskaya ◽

A L Syrkin

Keyword(s):

Parathyroid Hormone ◽

Left Ventricular Hypertrophy ◽

Primary Hyperparathyroidism ◽

Cardiovascular System ◽

Qt Interval ◽

Ventricular Hypertrophy ◽

Left Ventricular Diastolic Dysfunction ◽

Left Ventricular ◽

Ionized Calcium ◽

Mild Primary Hyperparathyroidism

The cardiovascular system was analyzed in patients with symptomatic (n = 31) and mild primary hyperparathyroidism (n = 34) whose mean age was 54.6 years; 95% females). In the patients with symptomatic primary hyperparathyroidism, the PQ interval was longer and the QT interval was significantly shorter than those in patients with mild hyperparathyroidism. Left ventricular hypertrophy was noted in 45.2% of patients with symptomatic and in 15.2% of those with mild hyperparathyroidism (p = 0.013). Left ventricular diastolic dysfunction was also more common in the group of symptomatic hyperparathyroidism. There was a statistically significant correlation between the levels of parathyroid hormone, total and ionized calcium and the duration of QT interval and the determinants of diastolic function and left ventricular hypertrophy. The revealed cardiovascular disorders in patients with primary hyperparathyroidism are presumed to depend on the increase rate of parathyroid hormone and total and ionized calcium.

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A Mathematical Model of Parathyroid Hormone Response to Acute Changes in Plasma Ionized Calcium Concentration in Humans

Volume 2: Biomedical and Biotechnology Engineering ◽

10.1115/imece2008-67551 ◽

2008 ◽

Cited By ~ 2

Author(s):

Rajiv P. Shrestha ◽

Yossi Chait ◽

Christopher V. Hollot ◽

Stuart Chipkin ◽

Claus P. Schmitt

Keyword(s):

Calcium Concentration ◽

Linear Time ◽

Ionized Calcium ◽

Time Varying ◽

Qualitative Model ◽

Hormone Response ◽

Clinical Tests ◽

Parametrization Scheme ◽

Normal Humans ◽

Acute Changes

A complex bio-mechanism, referred to as calcium homeostasis, regulates plasma ionized calcium (Ca++) concentration in the human body to within a narrow physiologic range which is crucial for maintaining normal physiology and metabolism. In this paper we present a qualitative model of the calcium homeostatic system and then focus on a particular sub-system, termed Ca-PTH axis. We consider the dynamics of the axis involving the response of the parathyroid glands to acute changes in plasma Ca++ concentration. We use a two-pool, linear time-varying model to describe the Ca-PTH axis. We show that this model, parameterized using a guided iterative parametrization scheme and induced hypocalcemic clamp test data, successfully predicts dynamics observed in clinical tests of induced hypercalcemia in normal humans.

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Acute Parathyroid Hormone Response: Sensitivity, Relationship to Hypocalcemia, and Rapidity

Endocrinology ◽

10.1210/endo-95-3-753 ◽

1974 ◽

Vol 95 (3) ◽

pp. 753-759 ◽

Cited By ~ 44

Author(s):

J.W. BLUM ◽

J.A FISCHER ◽

D. SCHWOERER ◽

W. HUNZIKER ◽

U. BINSWANGER

Keyword(s):

Parathyroid Hormone ◽

Hormone Response ◽

Response Sensitivity

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The Sigmoidal Parathyroid Hormone-Ionized Calcium Curve and the Set Point of Calcium in Hemodialysis and Continuous Ambulatory Peritoneal Dialysis

Peritoneal Dialysis International ◽

10.1177/089686089301302s119 ◽

1993 ◽

Vol 13 (2_suppl) ◽

pp. 476-479 ◽

Cited By ~ 7

Author(s):

Fabio Malberti ◽

Bruno Corradi ◽

Bruno Pagliari ◽

Dino Romanini ◽

Antonietta Gazo ◽

...

Keyword(s):

Peritoneal Dialysis ◽

Parathyroid Hormone ◽

Parathyroid Gland ◽

Continuous Ambulatory Peritoneal Dialysis ◽

Ionized Calcium ◽

Set Point ◽

High Incidence ◽

Adynamic Bone ◽

The Right ◽

Aluminum Intoxication

A high Incidence of adynamic bone disease not related to aluminum Intoxication has been reported In continuous ambulatory peritoneal dialysis (CAPD). Since reduced parathyroid hormone (PTH) secretion may predispose to adynamic bone, we Investigated whether parathyroid gland sensitivity may be depressed In CAPD in comparison with hemodialysis (HD). Thus we determined parathyraid function by the evaluation of the PTH-ionized calcium (ICa) relationship, which was obtained Inducing hypocalcemia and hypercalcemia In 19 CAPD and 18 HD patients with biochemical and histological evidence of mild (MILD) or severe (OF) hyperparathyroidism, but negative stainable bone aluminum. Either CAPD or HD patients with OF showed a shift to the right of the sigmoidal PTH-ICa curve in comparison with patients with MILD, greater set point of calcium, and maximal PTH stimulation and Inhibition. The PTH-lCa curve and the other parathyraid function parameters were not different in CAPD and HD patients within the same bone histological group. In conclusion, our data document that parathyroid gland activity Is stimulated either in CAPD and HD patients with OF, but is not depressed in CAPD patients in comparison with HD patients.

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