The administration of cinacalcet hydrochloride just before a haemodialysis session suppresses the transient rise in intact parathyroid hormone induced by a low-calcium dialysate: when should cinacalcet hydrochloride be administered?

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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Renagel® lowers serum phosphorus and intact parathyroid hormone in hemodialysis patients

American Journal of Kidney Diseases ◽

10.1016/s0272-6386(97)90357-7 ◽

1997 ◽

Vol 29 (4) ◽

pp. A5

Keyword(s):

Parathyroid Hormone ◽

Hemodialysis Patients ◽

Serum Phosphorus ◽

Intact Parathyroid Hormone

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Effects of clomiphene and tamoxifen in vivo on the bone-resorbing effects of parathyroid hormone and of high oral doses of calcitriol (1,25(OH)2D3) in rats with intact ovarian function consuming low calcium diet

Bone and Mineral ◽

10.1016/0169-6009(90)90104-n ◽

1990 ◽

Vol 8 (3) ◽

pp. 185-193 ◽

Cited By ~ 9

Author(s):

A. Goulding ◽

E. Gold ◽

L. Fisher

Keyword(s):

Parathyroid Hormone ◽

Ovarian Function ◽

Calcium Diet ◽

Low Calcium Diet ◽

Low Calcium ◽

Oral Doses

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The Circadian Rhythm of Intact Parathyroid Hormone-(1–84): Temporal Correlation with Prolactin Secretion in Normal Men

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jcem-71-6-1556 ◽

1990 ◽

Vol 71 (6) ◽

pp. 1556-1560 ◽

Cited By ~ 15

Author(s):

F. C. LOGUE ◽

W. D. FRASER ◽

D. ST. J. O'REILLY ◽

D. A. CAMERON ◽

A. J. KELLY ◽

...

Keyword(s):

Circadian Rhythm ◽

Parathyroid Hormone ◽

Temporal Correlation ◽

Prolactin Secretion ◽

Intact Parathyroid Hormone ◽

Normal Men

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Relation Between Low Calcium Intake, Parathyroid Hormone, and Blood Pressure

Hypertension ◽

10.1161/01.hyp.35.5.1154 ◽

2000 ◽

Vol 35 (5) ◽

pp. 1154-1159 ◽

Cited By ~ 70

Author(s):

Rolf Jorde ◽

Johan Sundsfjord ◽

Egil Haug ◽

Kaare H. Bønaa

Keyword(s):

Blood Pressure ◽

Parathyroid Hormone ◽

Calcium Intake ◽

Low Calcium

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Effect of a protease inhibitor on in vitro stability of intact parathyroid hormone

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1258/000456303763046166 ◽

2003 ◽

Vol 40 (2) ◽

pp. 188-190 ◽

Cited By ~ 6

Author(s):

N. R. Anderson ◽

J. Nicholas ◽

M. R. Holland ◽

R. Gama

Keyword(s):

Parathyroid Hormone ◽

Protease Inhibitor ◽

Protease Activity ◽

Intact Parathyroid Hormone ◽

In Vitro Degradation ◽

Glass Tubes ◽

Edta Plasma ◽

In Vitro Stability ◽

Baseline Sample

Background: We investigated whether increased protease activity explains the increased in vitro degradation of intact parathyroid hormone (iPTH) observed in serum when compared to EDTA plasma. Methods: Pre-dialysis blood samples for iPTH were taken from 11 patients with chronic renal failure and collected into plain glass tubes, tubes containing 200 KIU/mL aprotinin (a protease inhibitor) and EDTA tubes. All sample aliquots were separated at 20 min, 1 h, 2 h, 4 h, 8 h and 24 h post collection. Results: Over 24 h, iPTH concentrations remained unchanged in EDTA tubes. iPTH concentrations were significantly lower in both plain tubes ( P < 0·01) and aprotinin tubes ( P < 0·001) at 24 h when compared to the baseline sample (20 min). At 24 h, iPTH concentrations in EDTA tubes were higher than in plain tubes ( P < 0·001) and aprotinin tubes ( P < 0·01). The addition of aprotinin to plain tubes significantly reduced the degradation of iPTH ( P < 0·05) at 24 h. Conclusion: Aprotinin significantly reduces the in vitro degradation of iPTH in plain tubes at 24 h from 24·7% to 9·6%. We suggest that increased protease activity contributes to the decline in serum iPTH over time. As this is observed in serum and not plasma it suggests that the increased protease activity may be due to the clotting process.

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Serum intact parathyroid hormone levels in cats with chronic kidney disease

Pesquisa Veterinária Brasileira ◽

10.1590/s0100-736x2013000200015 ◽

2013 ◽

Vol 33 (2) ◽

pp. 229-235 ◽

Cited By ~ 4

Author(s):

Luciano H. Giovaninni ◽

Marcia M. Kogika ◽

Marcio D. Lustoza ◽

Archivaldo Reche Junior ◽

Vera A.B.F. Wirthl ◽

...

Keyword(s):

Chronic Kidney Disease ◽

Parathyroid Hormone ◽

Kidney Disease ◽

Stage Iv ◽

Control Group ◽

Intact Parathyroid Hormone ◽

Acid Base ◽

Acid Base Status ◽

Serum Ionized Calcium ◽

Progression Of Renal Disease

Chronic kidney disease (CKD) is frequently observed in cats and it is characterized as a multisystemic illness, caused by several underlying metabolic changes, and secondary renal hyperparathyroidism (SRHPT) is relatively common; usually it is associated with the progression of renal disease and poor prognosis. This study aimed at determining the frequency of SRHPT, and discussing possible mechanisms that could contribute to the development of SRHPT in cats at different stages of CKD through the evaluation of calcium and phosphorus metabolism, as well as acid-base status. Forty owned cats with CKD were included and divided into three groups, according to the stages of the disease, classified according to the International Renal Interest Society (IRIS) as Stage II (n=12), Stage III (n=22) and Stage IV (n=6). Control group was composed of 21 clinically healthy cats. Increased serum intact parathyroid hormone (iPTH) concentrations were observed in most CKD cats in all stages, and mainly in Stage IV, which hyperphosphatemia and ionized hypocalcemia were detected and associated to the cause for the development of SRHPT. In Stages II and III, however, ionized hypercalcemia was noticed suggesting that the development of SRHPT might be associated with other factors, and metabolic acidosis could be involved to the increase of serum ionized calcium. Therefore, causes for the development of SRHPT seem to be multifactorial and they must be further investigated, mainly in the early stages of CKD in cats, as hyperphosphatemia and ionized hypocalcemia could not be the only factors involved.

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