1
|
|
2
|
Olstad OK, Reppe S, Loseth OP, Jemtland R, Gautvik KM. Binding and cyclic AMP stimulation by N-terminally deleted human PTHs (3-84 and 4-84) in a homologous ligand receptor system. J Bone Miner Res 1997; 12:1348-57. [PMID: 9286750 DOI: 10.1359/jbmr.1997.12.9.1348] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have produced in yeast two human parathyroid hormone (hPTH) analogs with amino-terminal deletions, hPTH(3-84) and hPTH(4-84), employing the mating factor alpha (MF alpha) expression system. The authenticity of the polypeptides was demonstrated by amino-terminal analysis, amino acid composition, and molecular mass analysis. In cells (LLC-PK1) transfected with the human PTH/parathyroid hormone-related protein (PTHrP) receptor, using [125I-Tyr36]chickenPTHrP(1-36)NH2 as radioligand, binding studies revealed dissociation constants at equilibrium (Kd) for hPTH(3-84) and hPTH(4-84) of 4.7 and 8.0 nM, respectively, only slightly higher than natural recombinant hPTH(1-84) Kd = 2.3 nM). In comparison, [Nle8,18,Tyr34]bovinePTH(3-34)NH2 and [Tyr36]cPTHrP(1-36)NH2 showed equal Kd's of 1.9 nM. Neither of the N-terminally deleted hPTH analogs showed any detectable stimulation of cAMP production in the cells at concentrations below 20 nM. At supersaturated concentrations (500 nM) with receptor occupancy of more than 95% these hPTH analogs revealed about 15% rest agonism compared with that of hPTH(1-84). hPTH(1-84) and [Tyr36]cPTHrP(1-36)NH2 showed an equal half maximal cyclic adenosine monophosphate (cAMP) stimulation of about 0.8 and 0.7 nM, respectively. The hPTH analogs did not show any ability to antagonize cellular cAMP production induced by either hPTH or [Tyr36]cPTHrP(1-36)NH2. [Nle8,18,Tyr34]bPTH(3-34)NH2 did also not antagonize cAMP stimulation by hPTH, but inhibited [Tyr36]cPTHrP(1-36)NH2-induced cAMP production by 40% when present at a 1000 M excess. These distinct results related to PTH and PTHrP from different species are important to consider in experiments evaluating potential hPTH or PTHrP antagonism, and employment of a hPTH/PTHrP receptor model is a requirement.
Collapse
Affiliation(s)
- O K Olstad
- Institute of Medical Biochemistry, University of Oslo, Norway
| | | | | | | | | |
Collapse
|
3
|
Gardella TJ, Luck MD, Jensen GS, Usdin TB, Jüppner H. Converting parathyroid hormone-related peptide (PTHrP) into a potent PTH-2 receptor agonist. J Biol Chem 1996; 271:19888-93. [PMID: 8702701 DOI: 10.1074/jbc.271.33.19888] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Most of the bone and kidney-related functions of parathyroid hormone (PTH) and parathyroid hormone-related peptide (PTHrP) are thought to be mediated by the PTH/PTHrP receptor. Recently, a homologous receptor, the PTH-2 receptor, was obtained from rat and human brain cDNA libraries. This receptor displayed the remarkable property of responding potently to PTH, but not to PTHrP. To begin to define residues involved in the ligand specificity of the PTH-2 receptor, we studied the interaction of several PTH/PTHrP hybrid ligands and other related peptide analogs with the human PTH-2 receptor. The results showed that two sites in PTH and PTHrP fully account for the different potencies that the two ligands exhibited with PTH-2 receptors; residue 5 (His in PTHrP and Ile in PTH) determined signaling capability, while residue 23 (Phe in PTHrP and Trp in PTH) determined binding affinity. By changing these two residues of PTHrP to the corresponding residues of PTH, we were able to convert PTHrP into a ligand that avidly bound to the PTH-2 receptor and fully and potently stimulated cAMP formation. Changing residue 23 alone yielded [Trp23]hPTHrP-(1-36), which was an antagonist for the PTH-2 receptor, but a full agonist for the PTH/PTHrP receptor. Residues 5 and 23 in PTH and PTHrP thus play key roles in signaling and binding interactions, respectively, with the PTH-2 receptor. Receptor-selective agonists and antagonists derived from these studies could help to identify the biological role of the PTH-2 receptor and to map specific sites of ligand-receptor interaction.
Collapse
Affiliation(s)
- T J Gardella
- Department of Medicine, Harvard Medical School, Boston, Massachusetts 02114, USA
| | | | | | | | | |
Collapse
|
4
|
Olstad OK, Jemtland R, Loseth OP, Bringhurst FR, Gautvik KM. Expression and characterization of a recombinant human parathyroid hormone partial agonist with antagonistic properties: Gly-hPTH(-1-->+84). Peptides 1995; 16:1031-7. [PMID: 8532584 DOI: 10.1016/0196-9781(95)00069-v] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have produced and characterized a hPTH analogue with an amino-terminal extension of glycine, Gly-hPTH(-1-->+84) (denoted Gly-hPTH). The hormone analogue was synthesized in E. coli strain BJ5183 transformed with the expression plasmid pKKPTH, extracted from the bacterial pellet and purified by reverse-phase high performance liquid chromatography. Its chemical nature, as determined by amino acid composition analysis, N-terminal amino acid analysis, and mass spectrometry, showed the 9480-Da Gly-hPTH as the predominant species. Because f-Met-Gly-hPTH was the expected form encoded by the plasmid construct, the results indicate that the f-Met residue was efficiently removed from the precurser form. The following functional characteristics of Gly-hPTH were demonstrated. 1) In cells transfected with the human PTH/PTHrP receptor, the receptor binding affinity was reduced threefold compared to the authentic hPTH(1-84) produced by Saccharomyces cerevisiae (apparent Kds: 8.4 and 2.7 nM, respectively). 2) Using the same cells, Gly-hPTH showed 27-fold reduced potency compared to hPTH(1-84) in stimulating intracellular cAMP production (EC50: 32 and 1.2 nM, respectively). 3) Gly-hPTH demonstrated antagonist activity by reducing hPTH-induced cAMP production by 33 +/- 5% (mean +/- SD) when tested at a 1:1 molar ratio. In these studies the recombinant authentic hPTH(1-84) was used as standard for comparisons, and it showed an equal receptor binding affinity and cAMP production as the chemically synthesized peptide [Nle8,18,Tyr34]bovinePTH(1-34)-NH2.
Collapse
Affiliation(s)
- O K Olstad
- Institute of Medical Biochemistry, University of Oslo, Norway
| | | | | | | | | |
Collapse
|
5
|
Analogues of parathyroid hormone modified at positions 3 and 6. Effects on receptor binding and activation of adenylyl cyclase in kidney and bone. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)52390-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
6
|
Yamamoto I, Bringhurst FR, Potts JT, Segre GV. Properties of parathyroid hormone receptors on circulating bovine lymphocytes. J Bone Miner Res 1988; 3:289-95. [PMID: 2850727 DOI: 10.1002/jbmr.5650030307] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Binding of parathyroid hormone (PTH) to circulating bovine lymphocytes was studied using, as the radioligand, a synthetic sulfur-free analog of bovine PTH, [Nle8,Nle18,Tyr34]bPTH-(1-34)amide, which was labeled to high specific activity with 125I and was purified by reverse-phase high-performance liquid chromatography. Binding of PTH to lymphocytes satisfies several criteria indicative of a specific interaction between the hormone and its receptor. Specific binding is saturable at 3.3 fmoles of radioligand bound per 10(7) cells, occurs more rapidly at 37 degrees C than at lower temperatures, and reaches equilibrium within 2 hr at 15 degrees C. Inhibition of specific binding occurs with intact PTH, with biologically active PTH analog or fragment, and with synthetic PTH antagonists, but not with biologically inactive PTH fragments, or peptide hormones unrelated to PTH antagonists, but not with biologically inactive PTH fragments, or peptide hormones receptors on lymphocytes and those previously reported with receptors in canine renal membranes, and on rat osteosarcoma cells. The dissociation constant (Kd) is approximately 10(-9) M, as calculated from the association and dissociation rate constants. This correlates very closely both with the apparent Kd, as estimated from Scatchard analysis of radioligand saturation and competition studies, and with previously reported Kd of PTH receptors in canine renal membranes and on intact rat osteosarcoma and opossum kidney cells. In addition, the relative binding affinity of intact hormone and a synthetic PTH agonist to to receptors on lymphocytes correlates closely with the relative biologic potency of these peptides in stimulating adenylate cyclase in membranes from these cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- I Yamamoto
- Department of Medicine, Massachusetts General Hospital, Boston
| | | | | | | |
Collapse
|
7
|
Kemp BE, Moseley JM, Rodda CP, Ebeling PR, Wettenhall RE, Stapleton D, Diefenbach-Jagger H, Ure F, Michelangeli VP, Simmons HA. Parathyroid hormone-related protein of malignancy: active synthetic fragments. Science 1987; 238:1568-70. [PMID: 3685995 DOI: 10.1126/science.3685995] [Citation(s) in RCA: 266] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Peptides corresponding to the amino-terminal region of the parathyroid hormone-related protein (PTHrP) of humoral hypercalcemia of malignancy were synthesized. A 34-amino acid peptide, PTHrP(1-34), was two to four times more potent than bovine or human PTH(1-34) in bioassays promoting the formation of adenosine 3',5'-monophosphate (cAMP) and plasminogen activator activity in osteogenic sarcoma cells and adenylate cyclase activity in chick kidney membranes. Like parathyroid hormone itself, in which the activity resides in the first 34 residues, PTHrP peptides of less than 30 residues from the amino terminus showed substantially reduced activity. PTHrP(1-34) had only 6% of the potency of bovine PTH(1-34) in promoting bone resorption in vitro. PTHrP(1-34) strongly promoted the excretion of cAMP and phosphorus and reduced the excretion of calcium in the isolated, perfused rat kidney consistent with the symptoms seen in malignant hypercalcemia.
Collapse
Affiliation(s)
- B E Kemp
- University of Melbourne, Department of Medicine, Repatriation General Hospital, Heidelberg, Victoria, Australia
| | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
|
9
|
Caporale LH, Rosenblatt M. Parathyroid hormone antagonists effective in vivo. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1986; 208:315-27. [PMID: 3551538 DOI: 10.1007/978-1-4684-5206-8_40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
|
10
|
|
11
|
Zull JE, Chuang J. Preparation and characterization of radioactive monoiodotyrosine and diiodotyrosine derivatives of parathyroid hormone. Anal Biochem 1984; 140:214-22. [PMID: 6486408 DOI: 10.1016/0003-2697(84)90157-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Highly purified native parathyroid hormone was iodinated by the enzymatic method and separated from unlabeled hormone by isocratic HPLC. The separation system used also resolved iodohistidine, monoiodotyrosine, and diiodotyrosine forms of the hormone from one another. A simplified procedure for direct bioassay of the carrier-free, high specific activity, mono- and diiodinated parathyroid hormone (PTH) by the renal membrane adenylyl cyclase method was also developed. Both labeled forms of the hormone are very potent in this assay, but the iodinated forms appeared to give a lower Vmax than the native hormone. The methods for iodination, separation and biological characterization of this PTH tracer are exceptionally facile, inexpensive, and convenient.
Collapse
|
12
|
Goldring SR, Tyler GA, Krane SM, Potts JT, Rosenblatt M. Photoaffinity labeling of parathyroid hormone receptors: comparison of receptors across species and target tissues and after desensitization to hormone. Biochemistry 1984; 23:498-502. [PMID: 6322839 DOI: 10.1021/bi00298a015] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Cells derived from human giant cell tumors of bone and fibroblasts derived from human neonatal foreskin respond to parathyroid hormone (PTH) by increasing the intracellular and extracellular levels of adenosine cyclic 3',5'-phosphate (cAMP). Using photoaffinity labeling methods, we examined these cells for the presence of a PTH receptor or a binding subunit of a receptor complex. A previously designed biologically active and photolabile radioligand analogue of PTH was reacted with these intact cells. After photolysis, the cells were extracted, and the proteins were denatured, reduced, and separated by electrophoresis on sodium dodecyl sulfate (Na-DodSO4)-polyacrylamide gels followed by autoradiography. A single membrane component, Mr 70 000, was labeled specifically in intact cells cultured from skeletal and dermal tissue. By mixing, in pairs, photolabeled proteins from (a) intact human cells derived from giant cell tumors of bone, (b) intact human fibroblasts, and (c) canine renal cortical membranes, the receptors (or their binding subunits) for PTH were compared directly and found to be identical in terms of molecular size (as determined by the migration position on NaDod-SO4-polyacrylamide gels) across species (dog and human) and target tissue (bone, skin, and kidney). Preincubation of cells cultured from giant cell tumors of bone with PTH resulted in loss of the PTH-induced cAMP response (desensitization). Preincubation with PTH was accompanied by a marked decrease in photoaffinity labeling of the PTH binding component and suggests that the loss of hormone response in cells preincubated with PTH was related to a decrease in the number or availability of PTH receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|
13
|
Tyler GA, Rosenblatt M. Semi-preparative high-performance liquid chromatographic purification of a 28-amino acid synthetic parathyroid hormone antagonist. J Chromatogr A 1983; 266:313-8. [PMID: 6630356 DOI: 10.1016/s0021-9673(01)90905-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Structure-activity studies of parathyroid hormone (PTH) over the last decade have led to the design and synthesis of a peptide hormone inhibitor of PTH action in vivo, [Tyr-34]bPTH-(7-34)amide. To evaluate the biological properties of this 28-amino acid hormone analogue, sufficient amounts of the peptide needed to be prepared in a high state of purity to permit continuous infusion in groups of animals for periods of several hours. For this purpose, gel chromatography followed by semi-preparative, reversed-phase high-performance liquid chromatography (HPLC) using a lyophilizable solvent gradient system of acetonitrile in 0.1% trifluoroacetic acid was utilized. In a parallel purification scheme, gel filtration followed by ion-exchange chromatography was employed. Comparison of yields and product purity were determined by a battery of chemical analytical techniques. Semi-preparative HPLC generated a highly purified product; substantial heterogeneity was detected in the ion-exchange-purified material. The HPLC-purified product retains the biological activities of binding to PTH receptors in vitro and inhibiting PTH action in vivo.
Collapse
|
14
|
Horiuchi N, Rosenblatt M, Keutmann HT, Potts JT, Holick MF. A multiresponse parathyroid hormone assay: an inhibitor has agonist properties in vivo. THE AMERICAN JOURNAL OF PHYSIOLOGY 1983; 244:E589-95. [PMID: 6305202 DOI: 10.1152/ajpendo.1983.244.6.e589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Vitamin D-deficient rats subjected to thyroparathyroidectomy (TPTX) were used to evaluate in vivo the biological properties of native bovine parathyroid hormone (bPTH) and chemically synthesized fragments and analogues of the hormone on several parameters of hormone action: calcium and phosphorus fluxes, generation of cyclic adenosine 3',5'-monophosphate (cAMP), and the metabolism of 25-hydroxyvitamin D3 [25(OH)D3]. Vitamin D-deficient rats, after TPTX or sham operation, were intravenously infused with a nutrient containing 7.5 mM CaCl2 for 30 h. During the last 7 h, PTH or one of its analogues was infused intravenously at rates between 0.04 and 20 nmol/h. One hour after the start of the peptide infusion, tritiated 25(OH)D3 was injected. Urine was collected hourly for phosphate and cAMP determinations and, at the end of the experiment, blood was obtained to determine the relative accumulation of tritiated 1,25-dihydroxyvitamin D3 ([3H]1,25(OH)2D3). Infusion of bPTH-(1--84), bPTH-(1--34), human (h)PTH-(1--34), or [Nle8, Nle18, Tyr34]bPTH-(1--34) amide was accompanied by a comparable dose-dependent decrease in plasma phosphate and a dose-dependent increase in plasma calcium and [3H]-1,25(OH)2D3, and urinary excretion of phosphate and cAMP. An evaluation of [Nle8, Nle18, Tyr34]bPTH-(3--34) amide, a potent inhibitor of PTH action in vitro in the renal adenylate cyclase assay, revealed that the analogue possessed weak agonist properties in vivo. The analogue increased excretion of both cAMP and phosphate in the urine, decreased plasma phosphate levels, and increased the accumulation of [3H]-1,25(OH)2D3 in the plasma. This multiparameter model system should aid in the elucidation of the in vivo biological effects of PTH and its analogues.
Collapse
|
15
|
McGowan JA, Chen TC, Fragola J, Puschett JB, Rosenblatt M. Parathyroid hormone: effects of the 3-34 fragment in vivo and vitro. Science 1983; 219:67-9. [PMID: 6849118 DOI: 10.1126/science.6849118] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The biologically active fragment ofparathyroid hormone, consisting of residues 1-34, and its in vitro antagonist, fragment 3-34, were administered separately or in combination to chronically thyroparathyroidectomized dogs. These fragments were also studied in vitro with dog renal cortical membranes. Fragment 3-34 inhibited the stimulation of adenylate cyclase by fragment 1-34 in vitro, but had no agonist or antagonistic effects on renal phosphate transport in vivo.
Collapse
|
16
|
|
17
|
Potts JT, Kronenberg HM, Rosenblatt M. Parathyroid hormone: chemistry, biosynthesis, and mode of action. ADVANCES IN PROTEIN CHEMISTRY 1982; 35:323-96. [PMID: 6299077 DOI: 10.1016/s0065-3233(08)60471-4] [Citation(s) in RCA: 120] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
18
|
Rosenblatt M. The parathyroid hormone molecule: biological implications of structure. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1982; 151:521-34. [PMID: 6758522 DOI: 10.1007/978-1-4684-4259-5_56] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
19
|
Rosenblatt M, Coltrera MD, Shepard GL, Gray DA, Parsons JA, Potts JT. Sulfur-free parathyroid hormone analogues containing D-amino acids: biological properties in vitro and in vivo. Biochemistry 1981; 20:7246-50. [PMID: 6274393 DOI: 10.1021/bi00528a030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Three sulfur-free analogues of bovine parathyroid hormone (bPTH) containing D-amino acids were synthesized by the solid-phase method and their biological properties compared in an in vitro bioassay (rat renal adenylate cyclase assay), a receptor assay for parathyroid hormone (PTH) (canine renal membranes), and an in vivo bioassay (chick hypercalcemia assay). The analogue [Nle8,Nle18,D-Tyr34]-bPTH-(1-34)-amide, which was found to be more than 4 times as potent in vitro as unsubstituted PTH, is the most potent analogue of PTH yet synthesized. The enhanced potency was largely attributable to increased affinity for the PTH receptor. In vivo, however, this analogue was only one-third as potent as bPTH-(1-34). Cumulative evidence suggests that the nearly 15-fold decline in the relative potency when the compound was assayed in vivo is due to the substitution of norleucine for methionine. The other analogues, [D-Val2,Nle8,D-Tyr34]bPTH-(1-34)-amide and [D-Val2,Nle8,Nle18,D=Tyr34]bPTH-(2-34)-amide, were only weakly active in vitro and in vivo, indicating that substitution with D-amino acids at the NH2 terminus of PTH causes markedly diminished receptor affinity. In fact, the placement of a D-amino acid at the NH2 terminus is more deleterious to biological activity than is omission of amino acids at positions 1 and 2.
Collapse
|
20
|
Coltrera M, Potts J, Rosenblatt M. Identification of a renal receptor for parathyroid hormone by photoaffinity radiolabeling using a synthetic analogue. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)68658-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
|
21
|
Nussbaum S, Rosenblatt M, Potts J. Parathyroid hormone . renal receptor interactions. Demonstration of two receptor-binding domains. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)70445-1] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
22
|
Coltrera M, Rosenblatt M, Potts JT. Analogues of parathyroid hormone containing D-amino acids: evaluation of biological activity and stability. Biochemistry 1980; 19:4380-5. [PMID: 7417413 DOI: 10.1021/bi00559a035] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
|
23
|
Abstract
Theoretical analysis of the tertiary and secondary structure of parathyroid hormone was conducted. By combining interpretations from this analysis with chemical data available in the literature, certain structural features of the hormone are consistently predicted. The proposed model for the hormone contains two domains dominated by hydrophobic clustering of critical residues within each domain and separated by an exposed linker region. In the prediction of two domains with a linker region, the model is similar to that proposed by Fiskin et al. [Fiskin, A.M., Cohn, D.M. & Peterson, G.S. (1977) J. Biol. Chem. 252, 8261-8268], but it differs significantly in other respects. The proposed structural features are apparent in the bovine, human, and porcine species of hormone.
Collapse
|
24
|
Rosenblatt M, Tregear GW, Shepard GL, Tyler GA, Veroni M, Potts JT. Comparison of two solid-phase peptide syntheses of a 32-amino acid carboxyl-terminal fragment of human parathyroid hormone, hPTH-(53-84). Arch Biochem Biophys 1980; 199:286-96. [PMID: 7356337 DOI: 10.1016/0003-9861(80)90283-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|
25
|
Characterization of parathyroid hormone receptors in canine renal cortical plasma membranes using a radioiodinated sulfur-free hormone analogue. Correlation of binding with adenylate cyclase activity. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(18)50271-4] [Citation(s) in RCA: 128] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
26
|
Bialasiewicz AA, Jüppner H, Diehl V, Hesch RD. Binding of bovine parathyroid hormone to surface receptors of cultured B-lymphocytes. Biochim Biophys Acta Gen Subj 1979; 584:467-78. [PMID: 222343 DOI: 10.1016/0304-4165(79)90120-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Binding of parathyroid hormone onto B-lymphocytes is detected by the utilization of the labelled antibody membrane assay. The amount of parathyroid hormone bound to the receptor sites was depending on the quantity of cells in the incubation milieu. Each cell line showed typical characteristics in time course of parathyroid hormone binding and maximal receptor capacity. Fragmentation of intact parathyroid hormone, also varying with the cell line tested, was very rapid, even at 24 degrees C. Within 20 min most of the cell lines destroyed 20% of the native hormone in the incubation mixture, indicating a fragmentation rate of up to 2.25 ng/min at 37 degrees C. Bmax and KD for the different lymphocytes was 5.3--19 . 10(11) M and 1.8--18,5 . 10(11) M, respectively. These values are in the range of reported plasma concentrations and may therefore represent more physiological values for the capacity and affinity of membrane receptors.
Collapse
|
27
|
Raisz LG, Lorenzo J, Gworek S, Kream B, Rosenblatt M. Comparison of the effects of a potent synthetic analog of bovine parathyroid hormone with native bPTH-(1-84) and synthetic bPTH-(1-34) on bone resorption and collagen synthesis. Calcif Tissue Int 1979; 29:215-8. [PMID: 117885 DOI: 10.1007/bf02408083] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
An analog of bobine PTH [nle-8, nle-18, tyr-34 bPTH-(1-34) amide, (PTH-Ana)] which is a potent stimulator of renal adenylate cyclase has been compared with the native hormone bPTH-(1-84) and the biologically active amino terminal portion, bPTH-(1-34), for its effects on bone resorption and bone collagen synthesis in organ culture. All three compounds stimulated the release of previously incorporated 45Ca from cultured fetal rat long bone shafts with similar dose-response curves at 10(-9) to 3 X 10(-8) M. All three compounds inhibited bone collagen synthesis as measured by incorporation of proline into collagenase digestible protein, whereas incorporation into noncollagen protein was not inhibited. The effects were dose related and decreases in percent collagen synthesis were significant at 10(-9) M. Thus PTH-Ana appears to have the same effects on bone resorption and collagen synthesis as bPTH-(1-84) and (1-34) and is likely to be a valid probe for investigating PTH receptors in bone as well as in kidney.
Collapse
|