Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0272170 (SDS)
50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several types of specific insulin-like growth factor binding proteins have been reported. These binding proteins are produced by peripheral tissue-derived cells and they modulate the functions of insulin-like growth factors. In this study, we investigated both the secretion of insulin-like growth factor binding protein 3 (IGFBP-3) from a human osteosarcoma cell line MG63, and the effects of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) on the production of this binding protein. The beta subunit of IGFBP-3 was detected in perinuclear cytoplasm of MG63 cells by immunocytochemical study. Immunoblotting and SDS-PAGE analysis revealed that both 150KD MW entire molecules and 40-60KD MW beta subunit molecules of IGFBP-3 were present in cell-conditioned media. 1,25-(OH)2D3 stimulated the production of the IGFBP-3 molecule by MG63 cells. The concentration of IGFBP-3 in conditioned media began to rise at 12 hours after the addition of 10(-8) M of 1,25-(OH)2D3 and reached peak level at 48 hours. Dose-dependent effects of 1,25-(OH)2D3 were demonstrated. The its maximum effect was observed at 10(-10) M. The concentration of IGFBP-3 in cytosol also increased at a 10(-10) M concentration of 1,25-(OH)2D3. We conclude from these results that human osteosarcoma cells MG63 produce the IGFBP-3 molecule and that 1,25-(OH)2D3 stimulates the production of this protein. These data suggests that the synergistic effects of 1,25-(OH)2D3 on the action of IGF-I on osteoblastic cells, which we reported previously, may be modulated by locally produced IGFBP-3.
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PMID:1,25-Dihydroxyvitamin D3 stimulates the secretion of insulin-like growth factor binding protein 3 (IGFBP-3) by cultured human osteosarcoma cells. 137 Jul 89

The insulinlike growth factors (IGFs) circulate in association with insulinlike growth factor binding proteins (IGFBPs) that modulate IGF action, but mechanisms of IGFBP regulation are poorly understood. We investigated the regulation of IGFBPs in primary cultures of rat hepatocytes, measuring the appearance of export proteins by ligand blotting after separation via SDS/PAGE, and evaluating mRNA with cDNA probes. Northern blotting studies revealed that IGFBP-1 was expressed at high levels in cultured hepatocytes, in which sustained release of both insulinlike growth factor I and albumin marks preservation of differentiated status. In contrast, transcripts of IGFBP-3 and IGFBP-2 were not detected. Release of IGFBP-1 was unaffected by exposure to glucose (20-500 mg/dl) or to provision of amino acids (0.25-6.25 times normal rat arterial plasma levels). Hormonal studies revealed little effect of glucagon, inhibition by insulin, stimulation by dexamethasone, and blunting of dexamethasone effects by added insulin. Adding dexamethasone provided progressive stimulation: 5-, 11-, and 26-fold at 10(-9), 10(-8), and 10(-7) M, all P less than 0.01; increases in IGFBP-1 protein (ligand blot) and IGFBP-1 mRNA (Northern blot) were highly correlated (r = 0.62, P less than 0.001). In contrast, adding insulin resulted in progressive suppression of both IGFBP-1 protein and IGFBP-1 mRNA, 43% at 10(-10) M, 74% at 10(-9) M, and 83% (maximal) at 10(-8) M; ED50 of approximately 10(-10) M is within the physiological range of insulin concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Nutrition and somatomedin XXIX. Molecular regulation of IGFBP-1 in hepatocyte primary culture. 137 36

Insulin-like growth factor binding proteins (IGFBPs) in pregnant baboon serum and tissue culture media obtained following explant culture of uteri from pregnant baboons were characterized by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (2D SDS-PAGE) followed by Western ligand blot analysis using 125I-labeled IGF-I. IGFBP-1 (Mr 30,000; pI 4-4.2), IGFBP-2 (Mr 34,000, pI 5.7-6.2), IGFBP-3 (doublet Mr 42-48,000; pI 6.2-6.8), and IGFBP-4 (Mr 24,000; pI 5.7-6.0) were clearly separated from one another. The authenticity of IGFBP-1, -2, and -3 was verified by immunoprecipitation using polyclonal antibodies followed by ligand blotting. Specificity of 125I-labeled IGF-I binding to IGFBPs was also determined by competitive binding studies using unlabeled IGF-I and -II. This technique allows for the identification of IGFBPs in complex biological fluids on the basis of their characteristic Mr and pI with or without the availability of specific antibodies and can be done rapidly using the mini 2D SDS-PAGE systems.
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PMID:Characterization of insulin-like growth factor binding proteins by two-dimensional polyacrylamide gel electrophoresis and ligand blot analysis. 137 89

Human neonatal fibroblasts in monolayer culture secrete a number of insulin-like growth factor binding proteins (IGFBPs), including IGFBP-3, which may alter paracrine or autocrine IGF activity. Studies in vitro have demonstrated that exogenous IGFBP-3 can both inhibit and potentiate IGF action in these cells; however, it is not known to what extent there is regulatory interaction between the IGFBPs. In this study we report that exogenous and endogenous IGFBP-3 inhibit production of an IGF inducible IGFBP. When analyzed by SDS-PAGE and [125I]IGF-II ligand blotting, human neonatal fibroblasts secrete IGFBP-3, an IGFBP of 29-31 kDa, and a 22-24 kDa IGFBP after treatment with 50 ng/ml IGF-I. When IGF-I treatment was carried out in the presence of increasing concentrations (50-1000 ng/ml) of pure human serum-derived IGFBP-3, there was a dose-dependent decrease in the 29-31 kDa protein. In the presence of excess (250 ng/ml) IGF-I, IGFBP-3 had approximately 20-fold reduced potency in inhibiting 29-31 kDa IGFBP. When endogenous production of IGFBP-3 was increased by treatment with transforming growth factor-beta 1 (TGF beta 1), there was complete inhibition of 29-31 kDa IGFBP, while at high IGF-I concentrations TGF beta 1 had 2 to 3-fold reduced potency. These results demonstrate that fibroblast IGFBP production can be altered by exogenous and endogenous IGFBP-3, and suggest the existence of regulatory interactions between fibroblast IGFBPs.
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PMID:Inhibition of human fibroblast insulin-like growth factors binding protein (IGFBP) production by IGFBP-3. 138 Apr 45

Insulin-like growth factor-binding proteins (IGFBPs) in maternal and umbilical cord sera have been analysed by combinations of gel filtration chromatography, affinity cross-linking and electrophoresis. On gel filtration chromatography, the majority of circulating IGF-I in non-pregnant and pregnant women was present in the large molecular mass (150 kDa) binding proteins (IGFBP-3). In umbilical cord serum, by contrast, most IGF-I was present in the 40 kDa binding proteins (consisting of IGFBP-1 and IGFBP-2). Western blots demonstrated an apparent progressive attenuation of IGFBP-3 and IGFBP-2 in serum from pregnant women with an increase in IGFBP-1. After prior cross-linking with disuccinimidyl suberate, the 150 kDa fractions (IGFBP-3) from non-pregnant and pregnant serum showed a similar pattern on SDS-PAGE (several bands at different molecular masses). However, IGFBP-2 (one of the components of the 40 kDa fractions) was undetectable, even after cross-linking, in serum from pregnant women later than 8 weeks of gestational age and in a mixture of maternal serum at term delivery and serum from non-pregnant women. This suggests that serum IGFBP-2 was degraded by specific proteases present in pregnancy serum. Following acid treatment, the 150 kDa fractions from pregnancy serum were split into smaller subunits or fragments while the 40 kDa fractions remained unchanged, suggesting that the 40 kDa binding proteins, are acid-stable. The present data demonstrate that IGFBP-3 is the principal IGFBP in pregnancy serum even though there is an apparent reduction in serum IGFBP-3 activity as revealed on Western blots. The absence of IGFBP-2 in serum from pregnant women may be due to degradation by proteases. In the fetal circulation IGFBP-1 and IGFBP-2 appear to be the major binding proteins for IGF-1.
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PMID:Chromatographic characterization of insulin-like growth factor-binding proteins in human pregnancy serum. 138 9

Children with congenital CRF lose height potential mainly during two distinct growth periods; infancy and puberty. The onset of puberty is late, the pubertal growth spurt starts from a very low rate of growth velocity, and peak height velocity is lower than normal although the absolute increment of height velocity is comparable to the increment in normal children. Furthermore, the duration of pubertal growth spurt is reduced in CRF. During infancy and early childhood, malnutrition, electrolyte disturbances and metabolic acidosis are the main contributing factors for reduced growth, whereas hormonal disturbances are responsible for growth impairment during puberty. There is evidence for resistance to growth hormone in CRF, which starts in early childhood and persists until the end of puberty. Growth hormone secretion is normal in CRF, but GH half-life is prolonged. The binding activity of the stable growth hormone binding protein is reduced, which points to a low receptor expression in the liver. Hepatic IGF-I production is diminished. However, the serum concentration of IGF binding proteins (IGFBP) is increased due to reduced renal filtration of low molecular weight subunits of IGFBP. Mainly, the accumulation of IGFBP-3 leads to increased IGF-binding capacity of the uraemic serum. Both, reduced IGF-I production and increased binding of IGF to IGFBP-3 result in decreased IGF bioactivity. During infancy, loss of growth potential can be prevented by adequate nutrition. Later in life, catch-up growth cannot be induced by nutritional intervention or dialysis. Renal transplantation allows catch-up growth in only a small percentage of patients. Treatment with one IU rhGH/kg/week improves growth velocity and growth in all stages of renal disease. The mean increment of height in prepubertal children is +1.5 SDS within two treatment years. The effect of rhGH during puberty as well as the effect on final height remain to be determined.
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PMID:Growth failure in renal disease. 152 58

An assay for assessing the proteolysis of IGFBP-3 by a biological fluid or protein has been developed using 125IhIGFBP-3 recombinantly derived from Escherichia coli as a substrate indicator. The labelled substrate is incubated at 37 degrees in the presence of the agent being tested and proteolysis is visualized by SDS-PAGE and autoradiography. The assay showed that the pregnancy associated protease is Ca++ dependent. The substrate is also proteolyzed by rat and mouse pregnancy sera, making the assay applicable to studies in those animal systems.
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PMID:A simple assay for proteolysis of IGFBP-3. 170 77

Recombinant human insulin-like growth factor binding protein 3 (hIGFBP-3) stably expressed in chinese hamster ovary cells (CHO cells) has been purified to homogeneity from serum-free culture media. The purified protein migrates as a doublet (45/43 kDa) upon SDS-PAGE. The purified recombinant hIGFBP-3 is fully active and binds one mole of IGF-I per mole of recombinant binding protein. When the transfected CHO cells are treated with tunicamycin a single 29 kDa hIGFBP-3 protein is observed. This expressed hIGFBP-3 protein maintains its ability to bind IGF-I. N-Glycanase treatment of the purified hIGFBP-3 protein results in a protein that migrates similar to E. coli-derived IGFBP-3 upon SDS-PAGE under reducing conditions (30 kDa). Carboxymethylation of hIGFBP-3 suggests that all 18 cysteines are involved in disulfide linkages. These results represent the first purification and characterization of recombinant hIGFBP-3 expressed in CHO cells.
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PMID:Purification and characterization of human recombinant insulin-like growth factor binding protein 3 expressed in Chinese hamster ovary cells. 171 50

Cerebrospinal fluid insulin-like growth factor binding proteins (CSF IGFBPs) characteristically have a preferential affinity for IGF-II, which is largely accounted for by a 32-30 kDa IGFBP(Ka = 10(11) M-1) previously purified from human CSF, with an N-terminal sequence unlike any other IGFBP identified at the time. We have now used procedure (including ammonium sulphate precipitation, acidic gel filtration, affinity chromatography and reverse phase chromatography) and purified three further IGFBPs to homogeneity from child CSF. Apart from the 32-30-kDa form, the predominant IGFBP in CSF is a 34-kDa form (non-reduced in SDS-polyacrylamide gel electrophoresis). Like the 32-30-kDa IGFBP, it has a preferential affinity for IGF-II (Ka = 2 x 10(10) M-1). Its N-terminus, Phe-Arg-(/)-Pro-Pro-(/)-Thr-Pro-Glu-Arg-Arg-(/)-Gly-Pro-Pro-Pro-Val, corresponds to that deduced for IGFBP-2, except for the first three residues which were not found in the CSF IGFBP. Another form, of 30 kDa, has an N-terminus identical to IGFBP-3's over the first 18 residues determined and seems to be an altered form of IGFBP-3. A third minor species, of 22 kDa, with a preferential affinity for IGF-II similar to that of the 34-kDa IGFBP, has an N-terminal sequence, (/)-(/)-Asp-Ser-Phe-Val-Pro-(/)-Glu-Pro-Ser-Asp-Glu-Lys-Ala-Leu-Ser-(/)- (/)-Pro, which bears some analogy with those of other known human IGFBPs, particularly IGFBP-3 (7 homologous residues), and appears to be related to, but distinct from, other IGFBP species.
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PMID:Purification from human cerebrospinal fluid of insulin-like growth factor binding proteins (IGFBPs). Isolation of IGFBP-2, an altered form of IGFBP-3 and a new IGFBP species. 172 37

Cells of the human ovarian carcinoma lines EFO-21, EFO-27, MFO-35 and MFO-36 secrete binding proteins for insulin-like growth factors (IGFBPs) into their culture media. By sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE) and ligand blotting, seven groups of IGFBPs with molecular masses of 25, 30 (doublet), 34, 37, 40, 45, and 50 kDa were observed, depending on the cell line under investigation. By Northern blot analyses using cDNAs or oligonucleotides specific for the six types of IGFBP (IGFBP-1 to IGFBP-6), mRNA for all IGFBPs tested except for IGFBP-1 could be detected in the ovarian carcinoma cell extracts. In detail, analysis of EFO-21 protein products by SDS-PAGE yielded IGFBPs of 25, 34, and 50 kDa; extracts of EFO-21 cells contained mRNAs for IGFBP-2, -3, -4, and -6. EFO-27 cells produced IGFBPs of 40 kDa and 45 kDa as determined by SDS-PAGE, and mRNAs for IGFBP-3, -4, and -6 were detected. In the conditioned medium of MFO-35 cells, IGFBPs of 25, 30 (doublet), 34, 37, 40, and 45 kDa were observed by SDS-PAGE, while mRNAs for the five proteins IGFBP-2 to IGFBP-6 were found. MFO-36 cells produced IGFBPs of 34 kDa and 50 kDa as determined by SDS-PAGE, and the cells expressed mRNAs for IGFBP-2, -3, -4, and -6. In relation to published molecular mass data of the known IGFBPs, the size of the secreted proteins could be correlated to the mRNA patterns expressed by the ovarian carcinoma cells. It is concluded that ovarian carcinoma cells frequently express IGFBP-3, -4, and -6 and, to a lesser extent, IGFBP-2; the expression of IGFBP-5 appears as a rather rare event, while IGFBP-1 was not found to be expressed in ovarian carcinoma cells.
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PMID:Production of insulin-like growth factor binding proteins by human ovarian carcinoma cells. 750 72


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