Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A single dose of synthetic salmon calcitonin administered to rats (20 MRC U/kg body weight) stimulated the activity of ornithine decarboxylase in the brain, liver, kidney, testis and ovaries by 3-, 15-, 5-, 2- and 2-fold respectively after 4 h of the treatment. The increase in the enzyme activity in the brain, testis and ovaries was accompanied by a comparable increase in the enzyme protein content. Hepatic and renal ornithine decarboxylase concentration increased only by 2-fold. These results suggest that calcitonin influences polyamine biosynthesis through a tissue-specific regulation of the activity and/or the number of ornithine decarboxylase molecules.
Mol Cell Endocrinol 1987 Aug
PMID:Calcitonin induces ornithine decarboxylase in various rat tissues. 365 6

A procedure is described for the production of calcitonin-specific hybridomas which involves primary and secondary immunization of Balb/c mice in the hind footpads with free, synthetic human calcitonin and cell fusion of lymphocytes from popliteal lymphonodes with a P3 x 63 myeloma line. This protocol offers the following advantages: (a) it is short and easy to perform, (b) it requires small amounts of unconjugated antigen, and (c) it gives a high yield of antigen-specific IgG-secreting hybridomas. Routine screening was carried out by ELISA on solid phase calcitonin and binding of the monoclonals to free antigen was studied with calcitonin linked to biotin through a 13 carbon atom spacer. Monoclonal couples capable of simultaneously binding calcitonin in solution were found by pairing in all possible combinations 25 purified antibodies, in their unlabelled and biotinylated form, in a checkerboard matrix experimental system. Of the over 30 positive pairs identified, four were used in a one-step enzyme immunoassay for calcitonin determination on microtiter plates in a concn range between 0.1 and 5 ng/ml. With the detecting monoclonal directly conjugated to peroxidase with a heterobifunctional crosslinker, the range of the assay with one monoclonal pair was between 25 and 1000 pg/ml with an 18 hr incubation at 4 degrees C.
Mol Immunol 1987 Nov
PMID:Production of monoclonal antibodies to calcitonin and development of a two-site enzyme immunoassay. 369 66

The application of different approaches for preparing DNAs coding for peptide hormones was demonstrated. The libraries of human, bovine and porcine pituitaries cDNA were obtained starting from their total mRNAs. Screening of these libraries revealed clones containing human, bovine and porcine growth hormone sequences, cDNAs for bovine ACTH-beta-lipotropin precursor and for bovine and porcine prolactin. The gene of human calcitonin was created by combination of chemical and enzymatic synthesis. This synthetic gene was further cloned in pBR322. The expression of cloned human growth hormone cDNA under control of different Escherichia coli promoters was studied and physico-chemical and biological properties of the growth hormone produced by E. coli were tested.
Mol Biol (Mosk)
PMID:[Genetic engineering of peptide hormones]. 388 4

A microradioimmunoassay for cAMP was developed in order to analyse the effects of alpha-adrenergic agonists on vasopressin (AVP)-induced cAMP cell accumulation in single pieces of microdissected medullary (MCT) and cortical (CCT) rat collecting tubules. Under the experimental conditions chosen (4 min of incubation in the presence of a phosphodiesterase inhibitor), no cAMP could be detected either in the bathing solution or in non-stimulating samples of tubule. In MCT, 10(-6) M AVP stimulated cAMP generation up to 128.3 +/- 9.0 (SEM) fmoles per mm of tubule per 4 min, N = 11. The response was dose-dependent with a KA value below 10(-10) M AVP. The addition of norepinephrine (NE) (10(-5) M in the presence of propranolol) suppressed the larger part of the response to AVP (from 92% with 2 X 10(-11) M AVP to 76% with 10(-6) M AVP); the addition of 10(-7) M NE still reduced by 59% the MCT response to 10(-10) M AVP (26.2 +/- 5.9 vs. 64.0 +/- 6.4 fmoles/mm, N = 3). In CCT, 10(-5) M NE reduced by 84% the cAMP generation induced by 10(-10) M AVP (8.8 +/- 2.0 vs. 54.2 +/- 3.5 fmoles/mm, N = 3). This inhibitory action of NE against the AVP effect in CCT was mimicked by 10(-7) M clonidine; in MCT it was suppressed by phentolamine and yohimbine, but not by prazosin, suggesting that alpha 2-adrenoreceptors are involved. On the other hand, the addition of the alpha-agonists to the incubation solution produced no inhibition of the cAMP cell accumulations induced by glucagon, calcitonin and isoproterenol in CCT, or glucagon in MCT, an observation demonstrating that alpha 2-adrenergic agonists selectively inhibit vasopressin-dependent cAMP generation by these nephron segments.
Mol Cell Endocrinol 1984 Oct
PMID:Inhibition of alpha 2-adrenergic agonists on AVP-induced cAMP accumulation in isolated collecting tubule of the rat kidney. 614 67

Time- and dose-dependent changes in intracellular enzyme activities in kidney and bone from rats injected with calcitonin have been assessed by quantitative cytochemistry. The doses of salmon calcitonin given were similar to those suggested in the Pharmacopoeial rat hypocalcaemia bioassay (1-50 mIU/50 g body weight). The highest doses produced 30% inhibition of alkaline phosphatase activity, maximal within 20 min after injection, in cells of renal proximal tubules and a stimulation of calcium-dependent adenosine triphosphatase activity in kidney cortical and outer medullary cells. Alkaline phosphatase activity in the periosteal bone cells was markedly inhibited at the lowest doses. When doses of human and porcine calcitonins were given which would be equipotent with that of salmon calcitonin in the rat hypocalcaemia bioassay, the effect of the non-mammalian peptide on renal alkaline phosphatase activity was relatively greater than that of the mammalian peptides. Oxidized human calcitonin did not inhibit renal alkaline phosphatase activity even when an amount equivalent to 10 times the highest dose of the unmodified peptide was injected.
Mol Cell Endocrinol 1983 Dec
PMID:Quantitative cytochemical responses to exogenously administered calcitonins in rat kidney and bone cells. 622 49

Several polypeptide hormones of apparently diverse structure and function have a number of similarities which suggest that there may be common features in their mechanism of action. These hormones are all composed of a single linear sequence of about 30 amino acids; their hydrophobic amino acids are regularly spaced at every third or fourth amino acid residue, allowing them to form amphipathic structures which can interact with phospholipids; a fragment at or near their N-terminus is required for biological activity. These hormones include glucagon, beta-endorphin, parathyroid hormone and calcitonin. A model is proposed in which all regions of the hormone bind to the receptor with comparable affinity except for a small segment which, when intact, triggers a conformational change in the receptor resulting in a further stabilization of the hormone-receptor complex. The activity of partial sequences and chemically modified forms of beta-endorphin, parathyroid hormone and glucagon are discussed in relation to this model.
Mol Cell Biochem 1983
PMID:Relationships among several different non-homologous polypeptide hormones. 631 22

Different 3' coding exons in the rat calcitonin gene are used to generate distinct mRNAs encoding either the hormone calcitonin in thyroidal C-cells or a new neuropeptide referred to as calcitonin gene-related peptide in neuronal tissue, indicating the RNA processing regulation is one strategy used in tissue-specific regulation of gene expression in the brain. Although the two mRNAs use the same transcriptional initiation site and have identical 5' terminal sequences, their 3' termini are distinct. The polyadenylation sites for calcitonin and calcitonin gene-related peptide mRNAs are located at the end of the exons 4 and 6, respectively. Termination of transcription after the calcitonin exon does not dictate the production of calcitonin mRNA, because transcription proceeds through both calcitonin and calcitonin gene-related peptide exons irrespective of which mRNA is ultimately produced. In isolated nuclei, both polyadenylation sites appear to be utilized; however, the proximal (calcitonin) site is preferentially used in nuclei from tissues producing calcitonin mRNA. These data suggest that the mechanism dictating production of each mRNA involves the selective use of alternative polyadenylation sites.
Mol Cell Biol 1984 Oct
PMID:Calcitonin/calcitonin gene-related peptide transcription unit: tissue-specific expression involves selective use of alternative polyadenylation sites. 633 29

Alternative splicing of rat calcitonin (CT) gene transcripts resulting in the production of calcitonin gene-related peptide (CGRP) in neural tissue and of CT in the thyroid has been proposed by Rosenfeld et al. (1983b). We have recognized CGRP- and CT-like peptides in extracts of the human brain, pituitary and thyroid using a combination of gel filtration analysis and HPLC, and specific RIAs. Immunoreactive CGRP was estimated in a heterologous RIA using 125I-labelled rat CGRP as ligand and antibodies raised to the rat hormone, and human CT in a homologous RIA. The levels of CGRP and CT are measured against synthetic rat CGRP and monomeric human CT, respectively, and expressed in ng and micrograms equivalents (eq). The content of immunoreactive CGRP of the neocortex (n = 3), the cerebellar cortex (n = 6), the periventricular mesencephalic region (n = 3) and the thyroid (n = 5) was similar (mean +/- SE, 0.79 +/- 0.16 ng eq/g wet tissue, 1.51 +/- 0.14 ng eq/g, 1.84 +/- 0.12 ng eq/g and 5.0 +/- 0.9 ng eq/g, respectively), whereas pituitary glands (n = 21) and medullary thyroid carcinomas (n = 6) contained higher levels (31.3 +/- 5.1 ng eq/g and 7.66 +/- 5.42 micrograms eq/g, respectively). Immunoreactive CT was lowest in the neocortex, cerebellar cortex and the periventricular mesencephalon (0.31 +/- 0.07 ng eq/g, 0.30 +/- 0.09 ng eq/g and 0.26 +/- 0.09 ng eq/g, respectively), followed by the pituitary and thyroid (2.77 +/- 0.62 ng eq/g and 146 +/- 26 ng eq/g, respectively), and was highest in medullary thyroid carcinoma tissue (680 +/- 372 micrograms eq/g).(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Cell Endocrinol 1984 Jun
PMID:Calcitonin gene-related peptide in the human thyroid, pituitary and brain. 661 Dec 78

This report summarizes the relationship of calcitonin to phosphate. The hypocalcemic action of calcitonin is dependent upon phosphate, while the hypophosphatemic action is independent of calcium. Calcitonin moves phosphate into bone cells and bone fluid in contrast to reducing the movement of calcium from bone to blood. Calcitonin acts rapidly and at low doses on the osteocytes and lining cells at bone surfaces. Morphological changes can be identified within 7 min. This action causes the accumulation of an electron-dense material both in bone lining cells and their microenvironment. It is postulated that both the hypocalcemic action of calcitonin and its ability to cause an accumulation of material at bone surfaces may result from the movement of phosphate into these areas. The biochemical action which could produce the phosphate movement is unknown. The possibility is suggested that calcitonin increases phosphate transport into bone cells.
Mol Cell Endocrinol 1981 Dec
PMID:Calcitonin and phosphate. 679 42

The effects of calcitonin (CT) on the cellular transport and accumulation of Ca were studied in bone cells grown in primary culture. The following sequence of events was detected: (1) After 1--2 h of incubation with CT the initial rate of Ca influx into bone cells transiently increased. A longer incubation with CT (3--24 h), caused a gradual decrease in the initial rate of Ca influx, reaching a level below the control at 24 h. (2) After 2 h incubation with CT, efflux studies revealer Ca pool and (b) an increase in the accumulation of Ca in the slow-turnover Ca pool. (3) After 30 min of incubation with CT the amount of Ca in bone cells gradually increased and remained at a higher level for up to 24 h incubation with CT. It is suggested that the transient increase in the initial rate of Ca influx into bone cells, caused by CT, may provide the signal for the accumulation of Ca in the slow-turnover Ca pool, which is probably the mitochondria.
Mol Cell Endocrinol 1980 Jun
PMID:Effects of calcitonin on transport and intracellular distribution of exchangeable Ca2+ in primary culture of bone cells. 739


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