scholarly journals Amino-terminal form of parathyroid hormone in CKD

2010 ◽  
Vol 78 (1) ◽  
pp. 110-111 ◽  
Author(s):  
Hirotaka Komaba ◽  
Masafumi Fukagawa
Keyword(s):  
Parathyroid Hormone ◽  
Amino Terminal ◽  
Terminal Form

scholarly journals Overproduction and Secretion of a Novel Amino-Terminal Form of Parathyroid Hormone from a Severe Type of Parathyroid Hyperplasia in Uremia

2006 ◽  
Vol 1 (3) ◽  
pp. 525-531 ◽  
Author(s):  
Toshio Arakawa ◽  
Pierre D’Amour ◽  
Louise Rousseau ◽  
Jean-Hugues Brossard ◽  
Makoto Sakai ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Parathyroid Hyperplasia ◽  
Amino Terminal ◽  
Terminal Form ◽  
Severe Type

scholarly journals Amino-Terminal Form of Parathyroid Hormone (PTH) with Immunologic Similarities to hPTH(1–84) Is Overproduced in Primary and Secondary Hyperparathyroidism

2003 ◽  
Vol 49 (12) ◽  
pp. 2037-2044 ◽  
Author(s):  
Pierre D’Amour ◽  
Jean-Hugues Brossard ◽  
Louise Rousseau ◽  
Louise Roy ◽  
Ping Gao ◽  
...  
Keyword(s):  
Renal Failure ◽  
Parathyroid Hormone ◽  
Primary Hyperparathyroidism ◽  
Structural Integrity ◽  
Molecular Form ◽  
Healthy Individuals ◽  
Amino Terminal ◽  
Terminal Form ◽  
Minor Peak ◽  
A Minor

Abstract Background: To separate non-(1–84)parathyroid hormone [non-(1–84)PTH] from PTH(1–84), we developed new HPLC gradients and observed that the peak coeluting with hPTH(1–84) could be separated into two entities recognized by a cyclase-activating PTH (CA-PTH) assay that reacts with the first four amino acids of the PTH structure. Methods: Sera from six healthy individuals and five patients with primary hyperparathyroidism, and eight pools of sera from patients in renal failure were fractionated by HPLC. A total (T)-PTH assay reacting with the (15–20) region, the CA-PTH assay, and a COOH-terminal (C)-PTH assay with a (65–84) structure requirement were used to measure basal and fractionated PTH values. Results: T-PTH was higher than CA-PTH in all healthy controls [mean (SD), 3.13 (0.37) vs 2.29 (0.33) pmol/L; P <0.01] and in renal failure patients [47 (35.1) vs 33.4 (26.1) pmol/L; P <0.01]. By contrast, CA-PTH concentrations were similar to or higher than T-PTH in three of five patients with primary hyperparathyroidism [25.7 (26.1) vs 23.1 (24.2) pmol/L; not significant]. The CA-PTH assay reacted with the hPTH(1–84) peak and with a minor peak different from the non-(1–84) peak recognized by the T-PTH assay. This minor peak was not recognized by the T-PTH assay. It represented 8 (2)% of CA-PTH in controls, 25 (23)% in patients with primary hyperparathyroidism, and 22 (7)% in renal failure patients, assuming equimolar reactivity to hPTH(1–84) in the CA-PTH assay. It was not oxidized hPTH(1–84), which migrated differently on HPLC and reacted similarly in the CA and T-PTH assays. Conclusions: This new molecular form of PTH has structural integrity of the (1–4) region but presumably is modified in the region (15–20), which is usually recognized by the T-PTH assay. Its clinical implications remain to be defined.

scholarly journals Actions of the Small Molecule Ligands SW106 and AH-3960 on the Type-1 Parathyroid Hormone Receptor

2015 ◽  
Vol 29 (2) ◽  
pp. 307-321 ◽  
Author(s):  
Percy H. Carter ◽  
Thomas Dean ◽  
Brijesh Bhayana ◽  
Ashok Khatri ◽  
Raj Rajur ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Small Molecule ◽  
Hormone Receptor ◽  
Transmembrane Domain ◽  
Receptor Activation ◽  
Blood Calcium ◽  
Parathyroid Hormone Receptor ◽  
Peptide Analog ◽  
Amino Terminal ◽  
Small Molecule Ligands

Abstract The parathyroid hormone receptor-1 (PTHR1) plays critical roles in regulating blood calcium levels and bone metabolism and is thus of interest for small-molecule ligand development. Of the few small-molecule ligands reported for the PTHR1, most are of low affinity, and none has a well-defined mechanism of action. Here, we show that SW106 and AH-3960, compounds previously identified to act as an antagonist and agonist, respectively, on the PTHR1, each bind to PTHR1-delNT, a PTHR1 construct that lacks the large amino-terminal extracellular domain used for binding endogenous PTH peptide ligands, with the same micromolar affinity with which it binds to the intact PTHR1. SW106 antagonized PTHR1-mediated cAMP signaling induced by the peptide analog, M-PTH(1–11), as well as by the native PTH(1–9) sequence, as tethered to the extracellular end of transmembrane domain (TMD) helix-1 of the receptor. SW106, however, did not function as an inverse agonist on either PTHR1-H223R or PTHR1-T410P, which have activating mutations at the cytoplasmic ends of TMD helices 2 and 6, respectively. The overall data indicate that SW106 and AH-3960 each bind to the PTHR1 TMD region and likely to within an extracellularly exposed area that is occupied by the N-terminal residues of PTH peptides. Additionally, they suggest that the inhibitory effects of SW106 are limited to the extracellular portions of the TMD region that mediate interactions with agonist ligands but do not extend to receptor-activation determinants situated more deeply in the helical bundle. The study helps to elucidate potential mechanisms of small-molecule binding at the PTHR1.

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.”

Comparison of the effects of parathyroid hormone (PTH) and recombinant PTH-related protein on bicarbonate excretion by the isolated perfused rat kidney

1990 ◽  
Vol 126 (3) ◽  
pp. 403-408 ◽  
Author(s):  
A. G. Ellis ◽  
W. R. Adam ◽  
T. J. Martin
Keyword(s):  
Parathyroid Hormone ◽  
Rat Kidney ◽  
Urine Volume ◽  
Clinical Manifestations ◽  
Fractional Excretion ◽  
Bicarbonate Concentration ◽  
Isolated Perfused Rat Kidney ◽  
Amino Terminal ◽  
Fractional Excretion Of Sodium ◽  
Perfused Rat Kidney

ABSTRACT The isolated perfused rat kidney was used to study the effects of amino-terminal fragments of human parathyroid hormone, hPTH(1–34), bovine parathyroid hormone, bPTH(1–84) and of PTH-related proteins, PTHrP(1–34), PTHrP(1–84), PTHrP(1–108) and PTHrP(1–141) on urinary bicarbonate excretion. PTHrP(1–34) (7 nmol/l), bPTH(1–84) (5·5 nmol/l) and hPTH(1–34) (7 nmol/l) had similar effects in increasing bicarbonate excretion with respect to the control. At lower concentrations (0·7 nmol/l) all PTHrP components, but not hPTH(1–34) or bPTH(1–84) increased bicarbonate excretion significantly. Infusions of PTHrP(1–108) and PTHrP(1–141) at 0·7 nmol/l, while associated with a rise in urinary bicarbonate concentration and excretion during the early stages of perfusion, produced a sharp decline in bicarbonate concentration and excretion in the latter part of perfusion. The different peptides produced no significant differences in glomerular filtration rate, fractional excretion of sodium or urine volume. The absence of substantial differences between the effects of hPTH(1–34) and PTHrP(1–34) are as noted in previous studies. The differences between PTHrP(1–108)/PTHrP(1–141) and PTHrP(1–34) demonstrated here are consistent with (1) the clinical manifestations of acidosis in hyperparathyroidism and alkalosis in humoral hypercalcaemia of malignancy, and (2) an independent action of a component of PTHrP beyond amino acids 1–34. Journal of Endocrinology (1990) 126, 403–408

Properties of amino-terminal parathyroid hormone-related peptides modified at positions 11–13

Peptides ◽  
1990 ◽  
Vol 11 (6) ◽  
pp. 1139-1142 ◽  
Author(s):  
Harald Jüppner ◽  
Abdul-Badi Abou-Samra ◽  
Susumu Uneno ◽  
Ernestina Schipani ◽  
Henry T. Keutmann ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Amino Terminal

Homologous amino-terminal radioimmunoassay for rat parathyroid hormone

1991 ◽  
Vol 261 (2) ◽  
pp. E262-E268 ◽  
Author(s):  
M. S. Calvo ◽  
C. M. Gundberg ◽  
H. Heath ◽  
J. Fox
Keyword(s):  
Parathyroid Hormone ◽  
High Performance ◽  
Specific Binding ◽  
Rat Plasma ◽  
Cross Reactivity ◽  
Standard Curve ◽  
Amino Terminal ◽  
Antiserum Dilution ◽  
Normal Rat ◽  
Assay Detection

Existing radioimmunoassays for parathyroid hormone (PTH) in rat plasma are based on cross-reactivity of rat PTH (rPTH) with heterologous antisera. We used the synthetic NH2-terminal fragment of rPTH [rPTH-(1-34)] to develop a homologous radioimmunoassay for circulating PTH. An antiserum to rPTH-(1-34) was raised in a goat (G-813), and the same peptide was used as radioligand (125I) and standard. Purification of the label by high-performance liquid chromatography (HPLC) increased specific binding greater than twofold and sensitivity by 50-100%. With a final antiserum dilution of 1:70,000, maximum specific binding of 30-33%, nonspecific binding of 1-5%, and 50-microliters sample additions, the assay detection limit was 1.8-2.5 pmol/l. A midregional fragment of human PTH did not displace 125I-labeled rPTH-(1-34). HPLC of extracts of rat parathyroid glands and hyperparathyroid plasma showed only a single peak of immunoreactivity that eluted 2 min after rPTH-(1-34). Dose dilution curves for rat parathyroid gland extracts, rPTH-(1-34) added to rat plasma, and endogenous rat plasma PTH all paralleled the standard curve. Immunoreactive PTH (irPTH) was detectable in greater than 90% of fasting normal rat plasma and changed appropriately in response to hyper- and hypocalcemia induced by low-calcium and vitamin D-deficient diets, injections of calcium and EDTA, and after thyroparathyroidectomy. The normal range for rat plasma irPTH was less than 2.0-12 pmol/l, in general agreement with bioassay results of others. Thus rPTH-(1-34) is an excellent immunogen for raising antisera to rPTH, and assays incorporating it may be of great value in studying rat parathyroid physiology.

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