Parathyroid hormone metabolism and its potential as a uremic toxin

1980 ◽  
Vol 239 (1) ◽  
pp. F1-F12 ◽  
Author(s):  
E. Slatopolsky ◽  
K. Martin ◽  
K. Hruska
Keyword(s):  
Renal Failure ◽  
Parathyroid Hormone ◽  
Chronic Renal Failure ◽  
Biological Effects ◽  
Uremic Toxin ◽  
Terminal Portion ◽  
Single Chain ◽  
Biochemical Alterations ◽  
Amino Terminal ◽  
Carboxy Terminal

Secondary hyperparathyroidism is a universal complication of chronic renal failure. It has been proposed that the markedly elevated levels of immunoreactive parathyroid hormone (i-PTH) in uremia may represent a “uremic toxin” responsible for many of the abnormalities of the uremic state. Plasma i-PTH consists of a mixture of intact hormone, a single-chain polypeptide of 84 amino acids, and smaller molecular weight hormonal fragments from both the carboxy- and amino-terminal portion of the PTH molecule. The hormonal fragments arise from metabolism of intact PTH by peripheral organs as well as from secretion of fragments from the parathyroid glands. The structural requirements for the known biological actions of PTH reside in the amino-terminal portion of the PTH molecule. Carboxy-terminal fragments, biologically inactive at least in terms of adenylate cyclase activation, hypercalcemia, or phosphaturia, depend on the kidney for their removal from plasma, and thus accumulate in the circulation in chronic renal failure. It is unknown at the present time if other biological effects of these carboxy-terminal fragments may contribute to some of the biochemical alterations observed in uremia. The most significant consequence of increased PTH levels in uremia is the development of bone disease characterized by osteitis fibrosa. In addition, it would appear that PTH plays an important role in some of the abnormal electroencephalographic patterns observed in uremia. This may be due to a potential role of PTH in increasing calcium content of brain. Parathyroid hormone also has been implicated as a pathogenetic factor in many other alterations present in uremia, i.e., peripheral neuropathy, carbohydrate intolerance, hyperlipidemia, and other alterations. Unfortunately, outstanding clinical research is lacking in this field and conclusive experimental data are practically nonexistent. Further studies are necessary if one is to accept the concept of PTH being a significant “uremic toxin.”

scholarly journals Parathyroid hormone inhibits B cell proliferation: implications in chronic renal failure.

1990 ◽  
Vol 1 (3) ◽  
pp. 236-244
Author(s):  
J M Alexiewicz ◽  
M Klinger ◽  
T O Pitts ◽  
Z Gaciong ◽  
M Linker-Israeli ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Renal Failure ◽  
Parathyroid Hormone ◽  
Chronic Renal Failure ◽  
B Cells ◽  
B Cell ◽  
Normal Subjects ◽  
Dependent Manner ◽  
Dialysis Patients ◽  
Amino Terminal

B cell proliferation is impaired in patients with chronic renal failure, but the mechanisms underlying this defect are not known. Lymphocytes have receptors for parathyroid hormone, and it is possible that the state of secondary hyperparathyroidism of renal failure is responsible for the B cell defect. Our studies were designed to (a) examine T cell-independent B cell proliferation [3H)thymidine incorporation) induced by Staphylococcus aureus Cowan 1 after 5 days of culture, (b) evaluate the effect of parathyroid hormone on S. aureus Cowan I-induced B cell proliferation, and (c) investigate the mechanisms through which parathyroid hormone may exert its effect on B cell proliferation. Lymphocytes were obtained from 37 normal subjects and 21 dialysis patients. S. aureus Cowan I induced significant stimulation (P less than 0.01) of the proliferation of B cells from both groups, but the effect was smaller on B cells from dialysis patients (10.0 x 10(3) +/- 1.4 x 10(3) cpm) than on those from normal subjects (21.8 x 10(3) +/- 2.0 x 10(3) cpm). Both the intact molecule of parathyroid hormone (1-84 PTH) and its amino-terminal fragment (1-34 PTH) caused significant inhibition of proliferation of B cells from normal subjects in a dose-dependent manner, with the effect being significantly greater (P less than 0.01) with an equimolar concentration of 1-84 PTH than that of 1-34 PTH. Inactivation of 1-84 PTH by oxidation abolished most of its inhibitory effect on B cell proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Role of parathyroid hormone in the glucose intolerance of chronic renal failure.

1985 ◽  
Vol 75 (3) ◽  
pp. 1037-1044 ◽  
Author(s):  
M Akmal ◽  
S G Massry ◽  
D A Goldstein ◽  
P Fanti ◽  
A Weisz ◽  
...  
Keyword(s):  
Renal Failure ◽  
Parathyroid Hormone ◽  
Chronic Renal Failure ◽  
Glucose Intolerance

scholarly journals Parathyroid hormone secretion in chronic renal failure

1996 ◽  
Vol 50 (5) ◽  
pp. 1700-1705 ◽  
Author(s):  
Jesper C. Madsen ◽  
Anne Q. Rasmussen ◽  
Søren D. Ladefoged ◽  
Peter Schwarz
Keyword(s):  
Renal Failure ◽  
Parathyroid Hormone ◽  
Chronic Renal Failure ◽  
Hormone Secretion

Pregnancy decreases immunoreactive parathyroid hormone level in rats with chronic renal failure

1999 ◽  
Vol 96 (4) ◽  
pp. 427-430 ◽  
Author(s):  
M. BLUM ◽  
Y. WEISMAN ◽  
S. TURGEMAN ◽  
S. CABILI ◽  
Y. WOLLMAN ◽  
...  
Keyword(s):  
Renal Failure ◽  
Parathyroid Hormone ◽  
Chronic Renal Failure ◽  
Virgin Female ◽  
Normal Pregnancy ◽  
High Serum ◽  
Female Rats ◽  
Pregnant Rats ◽  
Serum Ipth ◽  
Immunoreactive Parathyroid Hormone

Normal pregnancy is associated with an increase in serum parathyroid hormone and 1,25-dihydroxyvitamin D3 (calcitriol). The effect of pregnancy on these hormones in chronic renal failure (CRF) is unknown. The present work was undertaken to study the changes of serum immunoreactive parathyroid hormone (iPTH) and calcitriol in pregnant rats with CRF. The following experimental groups were studied: CRF1 (5/6 nephrectomized virgin female rats), CRF2 (5/6 nephrectomized pregnant rats at day 20–21 of pregnancy), CRF3 (5/6 nephrectomized rats 2 weeks after delivery) and their respective sham-operated control groups: N1, N2 and N3. The 5/6 nephrectomy (CRF1) resulted in renal failure with very high serum iPTH (100±18 pg/ml) and low calcitriol levels (10.6±4.3 pg/ml) compared with normal rats [N1: 14±2.5 pg/ml (P< 0.001) and 18.2±4.2 pg/ml (P< 0.01) respectively]. The pregnancy in CRF rats (CRF2) resulted in normalization of serum iPTH levels (18.2±5.41 pg/ml), which was associated with a parallel increase in serum calcitriol (29.4±8.0 pg/ml) similar to that in pregnancy of normal rats (N2). Two weeks after delivery the CRF rats (CRF3) once again had high serum iPTH (87±17 pg/ml) and low calcitriol levels (9.3±1.2 pg/ml), similar to those observed in non-pregnant uraemic rats (CRF1). It is concluded that pregnancy decreases serum iPTH in 5/6 nephrectomized CRF rats most probably by the increased level of calcitriol synthesized by the feto-placental unit.

Parathyroid Hormone: Alterations in Chronic Renal Failure

Nephrology ◽  
1984 ◽  
pp. 1292-1304 ◽  
Author(s):  
Eduardo Slatopolsky ◽  
Kevin J. Martin ◽  
Jeremiah J. Morrissey ◽  
Keith A. Hruska
Keyword(s):  
Renal Failure ◽  
Parathyroid Hormone ◽  
Chronic Renal Failure

scholarly journals Impaired function of platelet membrane glycoprotein IIb-IIIa in end-stage renal disease.

1994 ◽  
Vol 5 (1) ◽  
pp. 36-46
Author(s):  
M P Gawaz ◽  
G Dobos ◽  
M Späth ◽  
P Schollmeyer ◽  
H J Gurland ◽  
...  
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Platelet Aggregation ◽  
Platelet Function ◽  
Uremic Toxin ◽  
Bleeding Tendency ◽  
Fibrinogen Receptor ◽  
Fibrinogen Binding ◽  
Uremic Patients ◽  
Stage Renal Disease

Impaired platelet function and a bleeding tendency are well-recognized complications of chronic renal failure. Because the fibrinogen receptor GPIIb-IIIa plays a central role in platelet aggregation and adhesion to the subendothelium, it was reasoned that a defect in this receptor may underlie the impaired platelet function in uremia. To test this hypothesis, the function of this receptor in the platelets of 11 uremic patients was studied. Aggregation studies were performed with flow cytometric techniques with anti-GPIIb-IIIa conformation-specific monoclonal antibodies (mAb) (anti-LIBS1 and anti-PMI-1). Antifibrinogen and antithrombospondin mAb were used to characterize fibrinogen binding to GPIIb-IIIa and the release of alpha-granules, respectively. Platelets from patients with chronic renal failure showed significantly decreased binding of conformation-dependent anti-LIBS1 mAb after ADP, phorbol myristate acetate, or RGD-peptide stimulation compared with normal controls, suggesting a defect related to the ability of the fibrinogen receptor to undergo a conformational change. Moreover, antifibrinogen and antithrombospondin binding to activated platelets were reduced in uremic patients, implying impairment of both ligand-binding and alpha-granule release. Hemodialysis partially restored GPIIb-IIIa function, which may account for the observed effects of this therapy in restoring platelet aggregation. These findings indicate that platelets of patients with chronic renal failure reveal an aggregation defect at least partially due to an intrinsic GPIIb-IIIa dysfunction and the presence of a putative uremic toxin that inhibits fibrinogen binding to GPIIb-IIIa.

Parathyrin radioimmunoassay: diagnostic utility of antisera produced against carboxyl-terminal fragments of the hormone from the human.

1978 ◽  
Vol 24 (3) ◽  
pp. 451-454 ◽  
Author(s):  
F P Di Bella ◽  
J M Kehrwald ◽  
K Laakso ◽  
L Zitzner
Keyword(s):  
Renal Failure ◽  
Parathyroid Hormone ◽  
Chronic Renal Failure ◽  
Guinea Pigs ◽  
Normal Subjects ◽  
Terminal Region ◽  
Diagnostic Utility ◽  
Human Origin ◽  
Widespread Availability ◽  
Carboxyl Terminal

Abstract Antisera directed toward the carboxyl-terminal region of human parathyrin (parathyroid hormone), for use in daignostically applicable radioimmunoassays of the hormone in serum, are scarce, largely because of the lack of suitable immunogens of human origin. We produced four antisera in goats and guinea pigs by immunization with recently discovered carboxyl-terminal fragments of human parathyrin extracted from parathyroid tumors. Here, we report results of radioimmunoassays of nearly 200 normal and pathological sera with one of these antisera; we observed almost complete differentiation between concentrations of parathyrin in serum of healthy normal subjects and patients with primary, secondary (due to chronic renal failure), or "ectopic" hyperparathyroidism (due to nonparathyroid cancer). The availability of a new immunogen should now make possible the deliberate production of large quantities of diagnostically applicable parathyrin antisera directed toward the carboxyl-terminal region of human parathyrin. This should, in turn, lead to more widespread availability of this useful radioimmunoassay.

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