Regulation of Parathyroid Hormone Secretion by Calcium in Man

ABSTRACT In 22 of 28 cases of primary hyperparathyroidism (PHP) the rise in the serum immunoreactive parathyroid hormone (IRPTH or PTH) level observed in response to lowering of the serum calcium by EDTA, exceeded that obtained in 8 control subjects. In 5 of these 22 patients who were studied again after parathyroidectomy the supranormal response was abolished. Fifteen of these 22 hyper-responsive PHP patients had basal IRPTH levels not exceeding the highest level in the controls and that of other groups of patients investigated (idiopathic hypercalciuria, non-parathyroid hypercalcaemia, operated PHP). Fourteen of the 22 hyper-reactive patients with PHP did not show hypocalcaemia during the infusion of EDTA. The extent of the release of PTH elicited by EDTA in cases of PHP does not as yet allow a prediction of the amount of pathological parathyroid tissue present, although all the PHP patients showing a normal release of PTH had a relatively small mass of parathyroid tissue (up to about 1 g) subsequently removed. In 9 cases of nephrolithiasis (8 of whom had idiopathic hypercalciuria) and in 7 cases of non-parathyroid hypercalcaemia, a normal PTH release was found.

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Ectopic parathyroid hormone secretion by a squamous cell carcinoma of the floor of the mouth with poor response to cinacalcet

Endocrine Abstracts ◽

10.1530/endoabs.70.ep107 ◽

2020 ◽

Author(s):

Ismene Bilbao ◽

Nerea Egaña ◽

Jorge Rojo ◽

Cristina Garcia ◽

Izaskun Olaizola ◽

...

Keyword(s):

Squamous Cell Carcinoma ◽

Parathyroid Hormone ◽

Cell Carcinoma ◽

Squamous Cell ◽

Hormone Secretion ◽

Poor Response ◽

Floor Of The Mouth ◽

Ectopic Parathyroid

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Thallium-Technetium Subtraction Scintigraphy of Enlarged Parathyroid Glands after Calcitonin Stimulation of Parathyroid Hormone Secretion

Acta Radiologica ◽

10.3109/02841859209173186 ◽

1992 ◽

Vol 33 (4) ◽

pp. 319-322 ◽

Cited By ~ 1

Author(s):

A. Bergenfelz ◽

J. Tennvall ◽

B. Ahren

Keyword(s):

Parathyroid Hormone ◽

Hormone Secretion ◽

Parathyroid Glands ◽

Stimulation Of ◽

Subtraction Scintigraphy

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Pulse amplitude and frequency modulation of parathyroid hormone secretion in man

Acta Endocrinologica ◽

10.1530/acta.0.117s171 ◽

1988 ◽

Vol 117 (4_Suppl) ◽

pp. S171 ◽

Cited By ~ 1

Author(s):

H. HARMS ◽

U. KAPTAINA ◽

T. KÜLPMANN ◽

R.-D. HESCH

Keyword(s):

Parathyroid Hormone ◽

Frequency Modulation ◽

Hormone Secretion ◽

Pulse Amplitude ◽

Amplitude And Frequency Modulation

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Effect of phorbol myristate acetate on secretion of parathyroid hormone

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1988.254.1.e63 ◽

1988 ◽

Vol 254 (1) ◽

pp. E63-E70 ◽

Cited By ~ 1

Author(s):

J. J. Morrissey

Keyword(s):

Protein Kinase C ◽

Parathyroid Hormone ◽

Protein Kinase ◽

Membrane Fraction ◽

Hormone Secretion ◽

Myristate Acetate ◽

Kinase C ◽

Low Calcium ◽

Protein Kinase C Activity ◽

High Calcium

The influence of phorbol myristate acetate (PMA), an activator of protein kinase c, on the secretion of parathyroid hormone from collagenase-dispersed bovine parathyroid cells was tested. The cells were incubated at low (0.5 mM) or high (2.0 mM) concentrations of calcium in the medium, and the hormone secreted into the medium was measured by a radioimmunoassay that recognizes both intact and C-terminal fragments of hormone. At low calcium, the secretory rate averaged 32 +/- 3.8 ng.h-1.(10(5) cells)-1. The addition of 1.6 microM PMA did not affect secretion. At high calcium there was a significant suppression of secretion by 38% to 19.8 +/- 3 ng.h-1.(10(5) cells)-1. The addition of 1.6 microM PMA significantly stimulated hormone secretion to 35.8 +/- 8 ng.h-1.(10(5) cells)-1, a rate indistinguishable from low calcium. This stimulatory effect of PMA at high calcium was seen at PMA concentrations as low as 1.6 nM, did not occur with a biologically inactive 4 alpha-isomer of phorbol ester, and was independent of changes in cellular adenosine 3',5'-cyclic monophosphate levels. Examination of 32P-labeled phosphoproteins by two-dimensional gel electrophoresis revealed acidic proteins of approximately 20,000 and 100,000 Da that were phosphorylated at low and high calcium + 1.6 microM PMA but not at high calcium alone. The protein kinase c activity associated with the membrane fraction of parathyroid cells significantly decreased 40% when the cells were incubated at high vs. low calcium. The data suggest that calcium may regulate parathyroid hormone secretion through changes in protein kinase c activity of the membrane fraction of the cell and protein phosphorylation.

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Parathyroid Hormone- and Deoxycorticosterone Acetate-Induced Hypertension in the Rat

Clinical Science ◽

10.1042/cs0580365 ◽

1980 ◽

Vol 58 (5) ◽

pp. 365-371 ◽

Cited By ~ 28

Author(s):

A. Berthelot ◽

A. Gairard

Keyword(s):

Parathyroid Hormone ◽

Hormone Secretion ◽

Sprague Dawley ◽

Physiological Concentration ◽

Deoxycorticosterone Acetate ◽

Calcium Diet ◽

Arterial Blood ◽

Sprague Dawley Rats ◽

High Calcium ◽

High Calcium Diet

1. Hypertension induced by treatment with deoxycorticosterone acetate and sodium chloride was studied in male Sprague-Dawley rats and related to parathyroid hormone secretion. 2. Lack of parathyroid hormone (due to parathyroidectomy) or decreased parathormone secretion (due to a high-calcium diet) partially inhibited the development of arterial hypertension. 3. In contrast, in thyroparathyroidectomized rats supplemented with thyroxine, the administration of parathyroid hormone rapidly elevated arterial blood pressure. 4. Maintaining a physiological concentration of serum calcium in the absence of parathyroid hormone (by feeding a high-calcium diet to parathyroidectomized rats) was not sufficient to establish mineralocorticoid hypertension. 5. These results show that parathyroid hormone is necessary for the complete development of mineralocorticoid hypertension.

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Divergent effects of forskolin on 3′,5′ cyclic adenosine monophosphate production and parathyroid hormone secretion

Calcified Tissue International ◽

10.1007/bf02405299 ◽

1984 ◽

Vol 36 (1) ◽

pp. 87-94 ◽

Cited By ~ 1

Author(s):

Larry K. Cantley ◽

Drusilla L. Scott ◽

Cary W. Cooper ◽

Darien D. Mahaffee ◽

George S. Leight ◽

...

Keyword(s):

Parathyroid Hormone ◽

Hormone Secretion ◽

Cyclic Adenosine Monophosphate ◽

Adenosine Monophosphate

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Parathyroid hormone secretion in chronic renal failure

Kidney International ◽

10.1038/ki.1996.488 ◽

1996 ◽

Vol 50 (5) ◽

pp. 1700-1705 ◽

Cited By ~ 2

Author(s):

Jesper C. Madsen ◽

Anne Q. Rasmussen ◽

Søren D. Ladefoged ◽

Peter Schwarz

Keyword(s):

Renal Failure ◽

Parathyroid Hormone ◽

Chronic Renal Failure ◽

Hormone Secretion

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Regulation of parathyroid hormone secretion by plasma calcium in aging rats

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1991.260.2.e220 ◽

1991 ◽

Vol 260 (2) ◽

pp. E220-E225 ◽

Cited By ~ 4

Author(s):

J. Fox

Keyword(s):

Parathyroid Hormone ◽

Hormone Secretion ◽

Fold Increase ◽

Male Rats ◽

Aged Rats ◽

Adult Rats ◽

Dihydroxyvitamin D3 ◽

Set Point ◽

Skeletal Resistance ◽

Immunoreactive Parathyroid Hormone

Plasma immunoreactive parathyroid hormone (irPTH) levels increase with aging. This study determined 1) whether NH2-terminal irPTH secretory responses to induced hypocalcemia differ between adult (6-mo-old) and aged (24- to 26-mo-old) male rats and 2) whether a higher set point for irPTH release by Ca is responsible for the elevated irPTH levels with aging. Basal irPTH levels were 68% higher and 1,25-dihydroxyvitamin D3 levels were 44% lower in aged rats. An acutely induced, constant hypocalcemic stimulus [0.32 mM decrement in ionized Ca (Ca2+) for 2 h] was developed in catheterized conscious adult and aged rats by ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) infusion using the Ca clamp technique. The initial irPTH secretory response to acute hypocalcemia (5-10 min) was reduced in aged rats (1.9- vs. 3.1-fold increase), suggesting reduced hormone stores. However, higher sustained irPTH levels (30 min to 2 h) were maintained in aged rats, indicating increased irPTH synthesis and release. The EGTA infusion rate necessary to maintain constant hypocalcemia was less in aged rats, suggesting skeletal resistance to PTH. Slow EGTA and Ca infusions were used to determine irPTH secretion at plasma Ca2+ levels from 0.7 to 1.5 mM. In aged rats, irPTH levels were higher at all Ca2+ concentrations, but the set point for irPTH release by Ca2+ was the same as in adult rats. Thus the elevated irPTH secretion in aged rats is not caused by a change in the set point for irPTH release but does result in decreased irPTH stores.

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