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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The alteration of regucalcin concentrations in the liver and serum of rats administered orally calcium is investigated. Rats received a single oral administration of calcium chloride solution (25, 50 and 75 mg Ca/100 g body weight). The administration of calcium (50 mg/100 g) produced a significant increase in liver regucalcin concentration between 30 and 180 min after the administration, while serum regucalcin concentration was not altered appreciably. The effect of calcium administration increasing liver regucalcin concentration was also seen with the dose of 25 mg/100 g. When liver cytosol prepared from normal rats was incubated for 6 h in the presence of 10 microM Ca2+, the cytosolic regucalcin concentration at 3 and 6 h of incubation was decreased about 20% (p < 0.05) as compared with the value at zero time point, indicating that the presence of Ca2+ does not inhibit the decomposition of liver cytosolic regucalcin. Moreover, serum regucalcin concentration was not significantly altered by the incubation for 6 h at 37 degrees C, indicating a stability of regucalcin in rat serum. This suggests that the calcium administration-induced in liver regucalcin concentration is not based on the inhibition of regucalcin release from liver to serum. The present study demonstrates that regucalcin in the liver is clearly increased by calcium administration, presumably due to stimulating the protein synthesis.
Mol Cell Biochem 1995 Feb 09
PMID:Calcium administration increases calcium-binding protein regucalcin concentration in the liver of rats. 777 58

The existence and expression of gene encoding the Ca(2+)-binding protein regucalcin in various species and tissues were investigated with Southern and Northern hybridization analyses using regucalcin cDNA (0.9 kb of open reading frame). Genomic Southern hybridization analysis demonstrated that regucalcin gene was widely conserved among higher animals including human, monkey, rat, mouse, dog, bovine, rabbit and chicken. The gene was not found in yeast. The Northern blot analysis of poly (A) +RNAs extracted from the liver of various species showed that regucalcin mRNA was predominantly expressed in rat and mouse, although the expression was also seen in human, bovine and chicken. Furthermore, the enzyme-linked immunoadsorbent assay (ELISA) with rabbit-anti-regucalcin IgG indicated that hepatic regucalcin concentration was most pronounced in rat as compared with that of guinea pig, mouse and chicken. These observations show that the gene expression of regucalcin and its protein synthesis is unique in the liver of rats, suggesting the existence of a specific mechanism in demonstrating regucalcin synthesis from gene.
Mol Cell Biochem 1995 Feb 09
PMID:Specific species and tissue differences for the gene expression of calcium-binding protein regucalcin. 777 60

The alteration of the plasma membrane (Ca(2+)-Mg2+)-ATPase activity in the liver of rats administered orally calcium chloride solution was investigated. The plasma membrane (Ca(2+)-Mg2+)-ATPase activity was significantly increased by a single oral administration of calcium (10, 25 and 50 mg/100 g body weight) in rats. This increase was seen between 10 and 60 min after the administration. The presence of anti-regucalcin IgG (1.0-5.0 micrograms/ml) in the enzyme reaction mixture caused a complete inhibition for the elevation of the plasma membrane (Ca(2+)-Mg2+)-ATPase activity by the addition of regucalcin (0.25 microM). Also, the calcium administration-induced increase in hepatic plasma membrane (Ca(2+)-Mg2+)-ATPase activity was completely abolished by the presence of anti-regucalcin IgG (1.0 and 2.5 micrograms/ml). Moreover, the calcium administration-induced increase in hepatic plasma membrane (Ca(2+)-Mg2+)-ATPase activity was not inhibited by vanadate (0.1 and 0.2 mM) addition into the enzyme reaction mixture, although the inhibitory effect of vanadate was seen in the plasma membranes from normal rat liver. Now, the activating effect of regucalcin (0.25 microM) on hepatic plasma membrane (Ca(2+)-Mg2+)-ATPase was not inhibited by vanadate addition. The endogenous regucalcin may play a role in the calcium administration-induced increase of (Ca(2+)-Mg2+)-ATPase activity in the liver plasma membranes of rats.
Mol Cell Biochem 1995 Mar 09
PMID:Increase of (Ca(2+)-Mg2+)-ATPase activity in hepatic plasma membranes of rats administered orally calcium: the endogenous role of regucalcin. 779 39

The involvement of a hypocalcemic hormone calcitonin (CT) in the expression of hepatic Ca(2+)-binding protein regucalcin mRNA was investigated. The change of regucalcin mRNA levels was analyzed by Northern blotting using liver regucalcin complementary DNA (0.9 kb). A single oral administration of calcium chloride (100 mg Ca/100 g body weight) to rats induced a remarkable increase in the serum calcium concentration and a corresponding elevation of the liver calcium content during 120 min after the administration. Thyroparathyroidectomy (TPTX) did not cause a significant increase in the liver calcium content after calcium administration. Hepatic regucalcin mRNA level was markedly elevated by calcium administration; the level was about 180% of controls at 60 min after the administration. This increase was completely abolished by TPTX. A single subcutaneous administration of CT (synthetic eel CT; 25-100 MRC mU/100 g) to TPTX rats received oral administration of calcium (100 mg/100 g) produced a remarkable increase in hepatic regucalcin mRNA levels; the level was about 280% of controls with the dose of 25 MRC mU CT/100 g. The present finding suggests that the expression of hepatic mRNA is stimulated by CT, and that the hormonal effect is mediated through Ca2+ in rat liver.
Mol Cell Biochem 1994 Jul 13
PMID:Expression of calcium-binding protein regucalcin mRNA in rat liver is stimulated by calcitonin: the hormonal effect is mediated through calcium. 785 30

The activating mechanism of regucalcin, a calcium-binding protein isolated from rat liver cytosol, on (Ca(2+)-Mg2+)-ATPase in the plasma membranes of rat liver was investigated. (Ca(2+)-Mg2+)-ATPase activity was markedly increased by a sulfhydryl (SH) group protecting reagent dithiothreitol (DTT; 2.5 and 5 mM as a final concentration), while the enzyme activity was significantly decreased by a SH group modifying reagent N-ethylmaleimide (NEM; 0.5-5 mM). The effect of DTT (5 mM) to increase the enzyme activity was clearly blocked by NEM (5 mM). Regucalcin (0.25-1.0 microM) significantly increased (Ca(2+)-Mg2+)-ATPase activity. This increase was completely blocked by NEM (5 mM). Meanwhile, digitonin (0.04%), which can solubilize the membranous lipids, significantly decreased (Ca(2+)-Mg2+)-ATPase activity. Digitonin did not have an effect on the DTT (5 mM)-increased enzyme activity. However, the effect of regucalcin (0.25 microM) increasing (Ca(2+)-Mg2+)-ATPase activity was entirely blocked by the presence of digitonin. The present results suggest that regucalcin activates (Ca(2+)-Mg2+)-ATPase by the binding to liver plasma membrane lipids, and that the activation is involved in the SH groups which are an active site of the enzyme.
Mol Cell Biochem 1994 Jul 13
PMID:Activating effect of regucalcin on (Ca(2+)-Mg2+)-ATPase in rat liver plasma membranes: relation to sulfhydryl group. 785 34

Whether calcium-binding protein regucalcin, which mainly localizes in liver, is released into the serum by liver injury was investigated in rats administered galactosamine. Galactosamine (25 mg/100 g body weight) was intraperitoneally administered 3 times at 2 h intervals in rats, and the animals were sacrificed at 10, 24 and 48 h after the first administration of galactosamine. Liver regucalcin mRNA levels were clearly reduced at 24 and 48 h after galactosamine administration with estimating for Northern blotting assay. When hepatic regucalcin concentration was estimated by enzyme-linked immunoadsorbent assay (ELISA) with rabbit-anti-regucalcin IgG, liver regucalcin concentration was not significantly altered by galactosamine administration. Serum regucalcin concentration was markedly elevated at 10 and 24 h after the first administration of galactosamine. Serum transaminases (GOT and GPT) activities were significantly increased by galactosamine administration, indicating that liver injury was induced. The present study demonstrates that liver regucalcin is released into the serum by liver injury with galactosamine administration in rats.
Mol Cell Biochem 1994 Jul 13
PMID:Serum release of hepatic calcium-binding protein regucalcin by liver injury with galactosamine administration in rats. 785 35

The effect of phenobarbital on the expression of calcium-binding protein regucalcin mRNA in rat liver was investigated. The change of regucalcin mRNA levels was analyzed by Northern blotting using liver regucalcin cDNA (0.9 kb of open reading frame). Phenobarbital (4, 8 and 12 mg/ 100 g body weight) was intraperitoneally administered to rats 3 times with 24 h intervals, and the animals were sacrificed by bleeding at 24 h after the last administration. The hepatic regucalcin mRNA levels were markedly reduced by phenobarbital administration. This decrease was about 50% of control level with the 12 mg/100 g dose. Moreover, the hepatic regucalcin concentration was significantly decreased by the administration of phenobarbital (12 mg/100 g), although the serum regucalcin concentration was not altered appreciably. Meanwhile, serum transaminases (GOT and GPT) activities were not increased by the administration of phenobarbital (4 and 12 mg/100 g). The present study demonstrates that the expression of hepatic regucalcin mRNA is decreased by phenobarbital administration in rats, suggesting that regucalcin does not have a role in drug metabolism related to phenobarbital.
Mol Cell Biochem 1994 Dec 07
PMID:Expression of hepatic calcium-binding protein regucalcin mRNA is decreased by phenobarbital administration in rats. 787 4

The change in calcium-binding protein regucalcin, mainly localized in liver, in the liver and serum of rats received a single oral administration of carbon tetrachloride (50%; 1.0 ml/100 g body weight) was investigated. The change of regucalcin mRNA levels in the liver was analyzed by Northern blotting using liver regucalcin cDNA (0.6 kb). At 10 and 24 h after the administration, liver regucalcin mRNA levels were reduced markedly. Moreover, regucalcin concentrations in the liver and serum was estimated by enzyme-linked immunoadsorbent assay (ELISA) with rabbit-anti-regucalcin IgG. Administration of carbon tetrachloride (CCl4) induced a significant decrease in liver regucalcin concentration and a corresponding elevation of serum regucalcin concentration at 24 h after the administration. An appreciable increase in serum regucalcin concentration was seen at 2 h after the administration. Meanwhile, serum transaminases (GOT and GPT) activities were significantly increased by CCl4 administration, indicating that liver injury is induced. The present study demonstrates that hepatic regucalcin is released into the serum of rats administered orally CCl4, suggesting that the estimation of serum regucalcin is a useful tool for diagnosis of liver injury.
Mol Cell Biochem 1994 Feb 23
PMID:Hepatic calcium-binding protein regucalcin in released into the serum of rats administered orally carbon tetrachloride. 803 83

The effect of various metals and regucalcin, a calcium-binding protein isolated from rat liver cytosol, on (Ca(2+)-Mg2+)-ATPase activity in the plasma membranes of rat liver was investigated. Of various metals (Zn2+, Cu2+, Ni2+, Mn2+, Co2+ and Al3+; 100 microM as a final concentration), Mn2+ and Co2+ increased markedly (Ca(2+)-Mg2+)-ATPase activity, while other metals had no effect. When Ca2+ was not added into enzyme reaction mixture, Mn2+ and Co2+ (25-100 microM) did not significantly increase the enzyme activity, indicating that heavy metals act on Ca(2+)-stimulated phosphorylation of the enzyme. Meanwhile, regucalcin (0.25-1.0 microM) caused a remarkable elevation of (Ca(2+)-Mg2+)-ATPase activity. This increase was not inhibited by the presence of 100 microM vanadate, although the effects of Mn2+ and Co2+ (100 microM) were inhibited by vanadate. Also, the inhibition of the Mn2+ and Co2+ effects by vanadate was not seen in the presence of regucalcin. Moreover, regucalcin (0.5 microM) increased significantly the enzyme activity in the absence of Ca2+. This effect of regulcalcin was not altered by increasing concentrations of Ca2+ added, indicating that the regucalcin effect does not depend on Ca2+. The present results suggest that regucalcin activates directly (Ca(2+)-Mg2+)-ATPase in liver plasma membranes, and that the activation is not involved in the Ca(2+)-dependent phosphorylation of the enzyme.
Mol Cell Biochem 1993 Jul 21
PMID:Regulatory effect of regucalcin on (Ca(2+)-Mg2+)-ATPase in rat liver plasma membranes: comparison with the activation by Mn2+ and Co2+. 823 87

The interaction of various hormones and regucalcin on (Ca(2+)-Mg2+)-ATPase activity in rat liver plasma membranes was investigated. The presence of epinephrine (10(-6)-10(-4) M), phenylephrine (10(-6)-10(-4) M), and insulin (10(-8)-10(-7) M) in the reaction mixture produced a significant increase in (Ca(2+)-Mg7+)-ATPase activity, while the enzyme activity was decreased significantly by calcitonin (3 x 10(-8)-3 x 10(-6) M). These hormonal effects, except for calcitonin, were clearly inhibited by the presence of vanadate (10(-4) M) which can inhibit the Ca(2+)-dependent phosphorylation of enzyme. Meanwhile, regucalcin (0.25 and 0.50 microM), isolated from rat liver cytosol, elevated significantly (Ca(2+)-Mg2+)-ATPase activity in the plasma membranes, although this elevation was not inhibited by vanadate (10(-4) M). The epinephrine (10(-5) M) or phenylephrine (10(-4) M)-induced increase in (Ca(2+)-Mg2+)-ATPase activity was disappeared in the presence of regucalcin; in this case the effect of regucalcin was also weakened. However, the inhibitory effect of calcitonin (3 x 10(-6) M) was not weakened by the presence of regucalcin (0.5 microM). Moreover, GTP (10(-5) and 10(-4) M)-induced increase in (Ca(2+)-Mg2+)-ATPase activity was not seen in the presence of regucalcin (0.25 microM). The present finding suggests that the activating mechanism of regucalcin on (Ca(2+)-Mg2+)-ATPase is not involved on GTP-binding protein which modulates the receptor-mediated hormonal effect in rat liver plasma membranes.
Mol Cell Biochem 1993 Aug 25
PMID:Regucalcin modulates hormonal effect on (Ca(2+)-Mg2+)-ATPase activity in rat liver plasma membranes. 828 72


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