Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: CAS:7440-70-2 (calcium)
 333,191 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Large quantities of parathyroid hormone-related protein (PTHrP) are present in the milk of various species. It has been suggested that PTHrP may play a role in neonatal calcium homeostasis. In the present study we evaluated the effect of neutralization of amino-terminal PTHrP activity by passive immunization in 1-day-old mouse pups. Neutralization of amino-terminal PTHrP activity had no significant effect on serum calcium or whole-body calcium content in the neonatal mice. In additional studies, we demonstrated that subcutaneous administration of PTHrP-(1-34) increased serum calcium, whereas oral administration had no significant effect in 3-day-old pups. The studies therefore demonstrate that the amino terminus of PTHrP may not play a significant role in neonatal calcium homeostasis. Local effects of PTHrP cannot be excluded by the results of the present study.
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PMID:Lack of effects of neutralization of parathyroid hormone-related protein on calcium homeostasis in neonatal mice. 180 44

The phylogenetic conservation of the primary structure of PTH-related protein (PTHrP) supports an important, yet undetermined, role(s) for this molecule in the biology of birds and mammals. As an initial step toward understanding the function of PTHrP in birds, we investigated the expression of PTHrP mRNA in tissues of the egg-laying hen. This analysis revealed that PTHrP mRNA is expressed at various levels in lung, brain, heart, and tissues of the digestive tract, including the proventriculus (secretory stomach), gizzard, and small intestine. In the oviduct tissues of adult birds, PTHrP mRNA was detected in the isthmus (membrane-secreting) and shell gland (calcium-secreting) portions, but not in magnum (albumin secreting) tissue. During oviduct development, high levels of PTHrP mRNA present in the oviducts of the 12-week-old bird suggest a role for PTHrP in oviduct development. Interestingly, as the oviduct matures, relatively high levels of PTHrP mRNA segregate with the distal tissues that ultimately differentiate into the isthmus and shell gland (uterus). To address a possible role for PTHrP in the differentiated function of the shell gland, we followed the expression of PTHrP in the shell gland at different times in the laying cycle and found levels of PTHrP to transiently increase as the egg moves through the oviduct, gradually returning to basal levels in the 15-h calcification period. We localized the cycle-associated fluctuations in PTHrP mRNA levels to the shell gland serosa and smooth muscle layer. Immunoreactive PTHrP was localized to the serosal membrane as well as the smooth muscle layer of serosal arterioles, suggesting that PTHrP may modulate vascular smooth muscle activity. In support of this hypothesis, synthetic chicken PTHrP (1-34)NH2 was found to relax the resting tension of isolated shell gland blood vessels in a dose-dependent manner. Together, these data indicate that the expression of the PTHrP gene in the avian oviduct is both temporally and spatially regulated during the egg-laying cycle and that PTHrP may function as an autocrine/paracrine modulator of shell gland smooth muscle activity of both ductal and vascular origins. The vasorelaxant property of N-terminal fragments of PTHrP supports a role for this molecule in the temporal increase in blood flow to the shell gland during egg calcification.
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PMID:Expression of the parathyroid hormone-related protein gene in the avian oviduct: potential role as a local modulator of vascular smooth muscle tension and shell gland motility during the egg-laying cycle. 184 56

PTH-related protein (PTHrP) has been implicated in calcium regulation during fetal life. In this study the ontogeny of PTHrP was examined in ovine parathyroid glands. Immunohistochemical techniques, Western blot analysis, and a RIA with antisera raised against synthetic fragments of human (h) PTHrP (i.e. 1-34, 1-40, 50-69, and 107-141) were used to detect the presence of immunoreactive PTHrP in parathyroid glands from fetal and neonatal lambs and maternal ewes. Positive immunostaining for PTHrP was observed in fetal (from 116 days of gestation) and lamb (up to 180 days post birth) but not maternal parathyroid glands with the PTHrP(50-69) antiserum. Fetal and lamb parathyroid glands consisted entirely of one cell type in which PTHrP immunoreactivity to PTHrP(50-69) antiserum was found. In contrast, immunoreactivity to PTHrP could not be detected in sections of fetal, lamb, or maternal parathyroid glands with antisera raised against PTHrP(1-34) or PTHrP(107-141). However, PTHrP immunoreactivity in urea/acid extracts of newborn lamb parathyroid glands could be detected by Western blot analysis and RIA with antisera raised against the N-terminal portion of PTHrP. Western blot analysis with the PTHrP(1-34) antisera revealed that urea/acid extracts of newborn lamb parathyroid glands contained a substance with a mol wt of 14.4K, which corresponded in size to that of hPTHrP(1-84). Newborn lamb parathyroid glands contained 0.35 ng PTHrP/micrograms extract, whereas maternal parathyroid glands contained only 0.035 ng PTHrP/micrograms extract when tested in a RIA employing recombinant hPTHrP(1-84) as standard and an antibody raised against hPTHrP(1-40). The detection of immunoreactive PTHrP in the developing ovine parathyroid gland provides further evidence to support the suggestion that PTHrP produced in the parathyroid gland is involved in the normal hormonal regulation of calcium metabolism in the mammalian fetus and neonate.
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PMID:Ontogeny of parathyroid hormone-related protein in the ovine parathyroid gland. 185 73

Interleukin (IL)-4 inhibits bone resorption. In the present study, the effect of IL-4 on hypercalcemia in nude mice under two experimental conditions was assessed. IL-4 inhibited plasma calcium elevation induced by parathyroid hormone-related protein (PTHrP) infusion. In hypercalcemic nude mice bearing PTHrP-producing tumors, IL-4 lowered plasma calcium levels to almost the normal range. These results indicate that IL-4 blocks PTHrP-induced hypercalcemia in vivo.
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PMID:Interleukin-4 blocks parathyroid hormone-related protein-induced hypercalcemia in vivo. 185 25

PTH-related protein (PTHrP) is commonly produced by squamous cell carcinomata and is the mediator of the PTH-like features of humoral hypercalcemia of malignancy. It has also been implicated in calcium regulation during fetal development. In this study immunohistochemical techniques, using rabbit polyclonal antibodies to synthetic PTHrP peptides, have been used to localize PTHrP in human fetal tissues from one fetus of 7 weeks and two of approximately 18 and 20 weeks gestation, respectively, in order to identify sites of potential functional significance. PTHrP immunoreactivity was identified in epithelia from many sources, including skin, bronchus, pancreas, pharynx, gut, stomach, and renal pelvis. Thyroid and parathyroid glands, which develop from epithelial origins, also stained positive for PTHrP, as did kidney collecting tubules, adrenal tissue, and skeletal and smooth muscle. PTHrP immunoreactivity was also located in developing long bones and calvaria, where it may have relevance in bone turnover during fetal development. The role of PTHrP at these locations remains to be elucidated, but the identification of specific PTHrP immunoreactivity in fetal epithelia is consistent with PTHrP production by cancers of epithelial origin and supports the hypothesis that PTHrP may have a role in epithelial growth and differentiation.
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PMID:Immunohistochemical detection of parathyroid hormone-related protein in human fetal epithelia. 187 27

A 72-year-old woman complaining of somnolence and thirst was diagnosed to have a hypercalcemic crisis (corrected serum calcium level, 17.4 mg/dl) associated with encephalopathy and nephropathy. Imaging diagnostic techniques demonstrated a retroperitoneal tumor at the median site of right renal pelvis. Hormonal studies revealed that plasma levels of thromboxane B2, prostaglandin (PG) E2, 6-keto prostaglandin F1 alpha (PGF1 alpha) and prostaglandin F2 alpha (PGF2 alpha) were markedly elevated. The tumor was successfully removed by operation; her serum calcium level and PG levels normalized without any treatment indicating that this case belongs to the category of humoral hypercalcemia of malignancy (HHM). Pathologically, this tumor was diagnosed to be a benign neurilemoma. Parathyroid hormone-related protein (PTHrP) radioimmunoassay and Northern blot hybridization for PTHrP mRNA were negative. The current case demonstrates that hypercalcemic crisis could be induced by a curable benign neurilemoma, and suggests that this HHM-like morbidity was associated with markedly elevated plasma PG levels.
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PMID:Retroperitoneal neurilemoma presenting with humoral hypercalcemia associated with markedly elevated plasma prostaglandin levels. 191 78

A 74-year-old male was urgently admitted to our hospital because of consciousness disturbance. Laboratory data showed remarkable hypercalcemia (7.8 mEq/L), hypophosphatemia, low % TRP, low intact PTH level, normal nephrogenic cyclic AMP and normal 1,25 (OH)2D level. Serum bone Gla protein, which was thought to express osteoblastic activity, was low. Serum tartarate resistant acid phosphatase and urinary excretion of hydroxyproline, which were thought to express osteoclastic activity, were high. CT scan showed an enlarged mass in the left renal pelvis, which was found to be a squamous cell carcinoma (SCC) by biopsy through percutaneous nephroscopy. Bone scintigram appeared normal. Therefore, we diagnosed it as renal pelvic SCC with humoral hypercalcemia of malignancy (HHM) and performed left nephrectomy. After nephrectomy, serum calcium returned to normal. But after a few weeks, lung metastasis appeared and serum calcium was reelevated. As to PTH related protein (PTHrP) which was thought to induce HHM, PTHrP content of the resected tumor measured by RIA assay was 13 pmol/g wet weight of tissue, which suggested that this tumor might have been producing PTHrP.
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PMID:[A case of renal pelvic squamous cell carcinoma accompanied with humoral hypercalcemia of malignancy]. 192 Oct 23

To elucidate the actual incidence of hypercalcemia in patients with esophageal carcinoma, 382 consecutive cases admitted to the National Cancer Center Hospital (Tokyo, Japan) from 1983 to 1988 were investigated. Hypercalcemia was detected in 5 patients of 376 (1.3%) at the time of primary detection of cancer, and in 45 patients of 120 (38%) patients with recurrent or unresectable cancer who were monitored within 2 months of death. These observations demonstrated that this electrolyte imbalance is a frequent paraneoplastic syndrome observed in patients with advanced esophageal carcinoma. With regard to the etiology, bone metastases were detected in 13 of 49 patients with hypercalcemia; the remaining 36 patients were assumed to be induced by the production of hypercalcemic substance(s) by tumor tissues. Parathyroid hormone-related protein (PTHrP) is a newly discovered factor which increases serum calcium in vivo. The detection of PTHrP mRNA in tumor tissues as well as the production of PTHrP-like immunoreactivity by tumor tissues were closely associated with the development of hypercalcemia, suggesting that PTHrP is the major cause of hypercalcemia in patients with esophageal carcinoma.
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PMID:Hypercalcemia in patients with esophageal carcinoma. The pathophysiologic role of parathyroid hormone-related protein. 193 13

Most lung carcinomas with hypercalcemia are usually unresectable. However, this case was resectable and the serum calcium level was normalized after the operation. Messenger RNA of the precursor of PTH-related protein (PTHrP), a substance that may be one of the causes of hypercalcemia in malignant neoplasms, was identified in the tumor tissue of the patient. The patient was a 60-year-old man with squamous cell carcinoma originating from the posterior basal segment of the left lung and invading the main bronchus and left atrium. The serum calcium level was 14.3 mg/dl, preoperatively. Pneumonectomy with partial left atrium resection was carried out and the serum calcium level became normal postoperatively. Three months following the operation, this measurement was 9.4 mg/dl, but increased to 16.2 mg/dl at four months, at which time he experienced lumbago and chest pain. The patient died eight months following the operation from uncontrollable renal failure. In the tumor tissue, mRNA of PTHrP precursor was identified. To our knowledge, this is the first case of lung cancer that could be resected, and in which PTHrP was found present.
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PMID:Hypercalcemia induced by parathyroid hormone-related protein from lung cancer tissue. 193 11

A RIA for PTH-related protein (PTHrP) is described, using a polyclonal goat antiserum against synthetic PTHrP-(1-40) and recombinant PTHrP-(1-84) as standard. The detection limit is 2 pmol/L, and intra- and interassay coefficients of variation are 4.8% and 13.6%, respectively. This assay does not detect PTH even at concentrations of up to 2000 pmol/L. Cross-reactivity studies using various synthetic PTHrP peptides localize the antibody-binding epitope between residues 20 and 29. Hypercalcemic patients with a range of solid tumors and no evidence of bone metastases on radionuclide scanning (n = 27) all had detectable PTHrP levels (range, 2.8-51.2 pmol/L). Of 17 patients with solid tumors (other than breast) and bone metastases, 11 (64%) also had detectable PTHrP levels (range, 4.9-47.5 pmol/L). Twenty samples from breast cancer patients with hypercalcemia, 19 with evidence of bone metastases, and 1 with a negative bone scan were assayed, and detectable PTHrP levels were found in 13 (65%; range, 3.8-61.6 pmol/L). Patients with squamous cell carcinomata and normal serum calcium levels (n = 11) had no detectable PTHrP or levels close to the detection limit of the assay (range, less than 2 to 3.7 pmol/L). Plasma levels in normal volunteers were below the detection limit of the assay in all but 1 of 38 normal subjects. Patients with chronic renal failure on hemodialysis (n = 18) and patients with primary hyperparathyroidism (n = 14) all had undetectable PTHrP in this assay. This assay allows positive identification of patients with PTHrP-mediated hypercalcemia and, therefore, should be useful in the clinical investigation of the hypercalcemic patient. Furthermore, it has allowed detection of circulating PTHrP in hypercalcemic breast cancer patients with bone metastases, indicating a significant role for PTHrP in this disease.
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PMID:Parathyroid hormone-related protein: elevated levels in both humoral hypercalcemia of malignancy and hypercalcemia complicating metastatic breast cancer. 195 13


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