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: EC:2.6.1.1 (aspartate aminotransferase)
21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pretreatment with Mn2+ is known to produce tolerance to Cd2+-induced lethality. This study was designed to determine the mechanism of tolerance to Cd2+-induced lethality and hepatotoxicity following Mn2+ pretreatment. Rats given 36 mumoles Cd2+/kg, i.v., died within 10-20 hr while only one of nine rats pretreated with Mn2+ (250 mumoles/kg, s.c., 48 and 24 hr prior to Cd2+ challenge) died. Ten hours after Cd2+, plasma aspartate aminotransferase and sorbitol dehydrogenase activities were elevated markedly, and extensive histopathologic lesions of the liver were evident in control rats but not in Mn2+-pretreated rats. To examine the mechanism of this tolerance, distribution of Cd2+ to fourteen organs and the subcellular distribution in six organs were determined in control and Mn2+-pretreated rats. Two hours after challenge (31 mumoles Cd2+/kg, i.v., 0.75 microCi 109Cd2+/mumol Cd2+), the distribution of Cd2+ to liver markedly increased after Mn2+ pretreatment with concomitant decreases in other tissues. Mn2+ pretreatment also resulted in a marked difference in the hepatic subcellular distribution of Cd2+ with more present in cytosol and less associated with organelles. Gel-filtration chromatography indicated that most cytosolic Cd2+ was bound to a low molecular weight protein. Isolation and partial characterization of this protein suggest that it is identical to metallothionein (MT); it had a similar relative elution following gel-filtration chromatography, had low absorbance at 280 nm and, after separation into two isoproteins by DEAE A-25 anion exchange chromatography, had the same mobility after electrophoresis on non-denaturing polyacrylamide gels as Cd2+-induced metallothioneins. These data suggest that Mn2+ pretreatment reduces Cd2+-induced hepatotoxicity by altering the hepatic subcellular distribution of Cd2+ with more Cd2+ binding to MT in the cytosol. This decreased hepatotoxicity is probably responsible for tolerance to Cd2+-induced lethality.
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PMID:Mechanism of manganese-induced tolerance to cadmium lethality and hepatotoxicity. 399 53

Vitamin D-depleted and vitamin D-replete rats were treated with allyl alcohol (AA) or bromobenzene (BB). The severity of the hepatotoxicity was evaluated by the serum concentrations of aspartate aminotransferase, alanine aminotransferase and sorbitol dehydrogenase, the histomorphological appearance of the lesions, and the amount of cytochrome P-450 destroyed. The activity of the monooxygenases was also evaluated. All parameters indicated that vitamin D depletion alone did not lead to any signs of liver toxicity nor did it modify the pattern of toxicity of either AA or BB. However, the intensity of the response in the periportal (AA treatment) and in the centrilobular (BB treatment) zones was modified by the depletion. Vitamin D depletion was accompanied by increased hepatic damage due to AA while BB resulted in less hepatic damage in vitamin D-depleted compared to vitamin D-replete animals. The metabolic profile of the liver mixed function oxidases indicated that its intraacinar distribution was modified by the depletion. Although the overall activity toward the substrates studied was not changed by vitamin D depletion, two out of the three enzyme activities studied suggested that vitamin D-depleted rats were poorer "centrilobular metabolizers" and better "periportal metabolizers" than vitamin D-replete rats. These observations correspond to increased periportal and decreased centrilobular toxicity in vitamin D-depleted animals. These results suggest that vitamin D depletion associated with severe hypocalcemia may be associated with an intraacinar modulation of enzyme systems as well as with an intraacinar difference in the susceptibility of the liver to certain chemicals.
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PMID:Comparative hepatic response to bromobenzene and allyl alcohol in the vitamin D-replete and vitamin D-depleted rat. 399 32

The electrophoretic separations of some human and pig liver enzymes on cellulose acetate and Cellogel were investigated, with reference to their joint occurrence in serum of patients undergoing treatment by extracorporeal pig liver perfusion. In every case it was possible to distinguish between the human and pig enzymes. Pig lactate dehydrogenase isoenzymes occupy a position slightly anodic to the corresponding human bands. The aspartate transaminase band of human is more anodic than that of pig, but their cathodic bands have the same mobility. Alanine transaminase of both human and pig liver extract is shown to exist as two bands each towards the anode. The faster moving human band is more anodic than the corresponding pig band, while the other human band is less anodic. Sorbitol dehydrogenase, alkaline phosphatase, and ornithine carbamoyltransferase all exist as one band each. Human sorbitol dehydrogenase is more cathodic than the pig enzyme, human alkaline phosphatase more anodic than the pig enzyme, while human ornithine carbamoyltransferase is less anodic than the pig enzyme.
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PMID:Electrophoretic separation and differentiation of enzymes from human and from porcine liver. 504 73

The effects of a diet containing a high proportion of rapeseed meal on the activity of certain plasma enzymes were studied in laying birds. The enzymes studied were alkaline phosphatase (AP), aspartate transaminase (AST), L-gamma-glutamyl-transferase (gamma-GT), isocitrate dehydrogenase (ICDH), leucine arylamidase (LAP), malate dehydrogenase (MDH) and sorbitol dehydrogenase (SDH). No notable differences were observed between the plasma AP, LAP or SDH activities of the birds given the rapeseed meal and the birds receiving a soyabean meal control diet throughout the experiment. However, the plasma AST and gamma-GT activities of the treated birds showed slight elevations while their plasma ICDH and MDH activities showed more marked elevations, which are indicative of liver damage, in response to the diet. Macroscopic observations of the livers of the birds at the end of the experiment were in fairly good accord with the elevation in plasma ICDH and MDH activities noted for the individual birds.
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PMID:Plasma enzyme activities indicative of liver cell damage in laying fowl given a diet containing 20 per cent of rapeseed meal. 610 67

Feeder pigs weighing 12 to 15 kg each were given a single oral dose of aflatoxin, 1.2 mg/kg of body weight. Liver-specific serum enzyme activities were compared with gross, microscopic, and ultrastructural hepatic changes in individual pigs euthanatized at 24, 48, and 72 hours after they were given aflatoxin. The greater the morphologic change in liver of the treated pigs, the greater the increase in liver-specific serum enzyme activities. Isocitric dehydrogenase, alkaline phosphatase, sorbitol dehydrogenase, and aspartate aminotransferase activities increased in 6 of 8 treated pigs by 24 hours. Increase in gamma-glutamyl transpeptidase activity was not significant. Microscopic and ultrastructural changes in centrilobular hepatocytes included glycogen deletion, mitochondrial and endoplasmic reticulum swelling, membrane disruption, and nuclear fragmentation at 24 hours. The centrilobular areas had marked extravasation of erythrocytes at 24 hours without basal lamina changes. At 72 hours, the centrilobular hepatocytes had increased lipid vacuoles and acceptable amounts of glycogen. Marked infiltrations of monocytes, plasma cells, and lymphocytes were also present at this time.
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PMID:Acute aflatoxicosis in swine: clinical pathology, histopathology, and electron microscopy. 612 94

The activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), ornithine carbamoyltransferase (OCT), sorbitol dehydrogenase (SDH), gamma-glutamyl transferase (GGT), alkaline phosphatase (AP), lactate dehydrogenase (LDH) and creatine kinase (CK), were determined in eight organs of 10 healthy male blue foxes. OCT was absolutely liver specific and ALT was also found to be liver specific. SDH was also found primarily in the liver but its activity was relatively low. GGT was found almost exclusively in the kidneys. The highest levels of AP were observed in the kidneys and in the intestines. LDH together with AST was present in high activities in all the tissues tested. CK activity was highest in skeletal and cardiac muscles.
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PMID:Activities of some enzymes in the tissues of the blue fox (Alopex lagopus). 613 May 87

Serum alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), 5'nucleotidase (5'NT), sorbitol dehydrogenase (SDH), and aspartate transaminase activities were measured in 10 clinically healthy foals, 10 yearlings, and 10 two-year-old Quarter Horses. Enzyme activities in foals at 0.5 to 3 days, 2 to 3 weeks, and 5 to 7 weeks of age were compared with enzyme activities from yearling and 2-year-old horses. Multivariate analyses of variance revealed significantly higher enzyme values in foals (P less than 0.002). This increase was mainly a result of higher ALP and GGT activities, with lesser effects due to higher SDH and 5'NT activities. Standard deviations for ALP and GGT were also larger in foals than in adult horses. The wide variation of ALP and GGT activities may limit their usefulness in the diagnosis of hepatic disease in foals. Standard deviations for serum AST, SDH, and 5'NT activities were smaller. These enzymes may be indicators of hepatobiliary disease in foals. The high serum enzyme activities in healthy foals may reflect a physiologic difference between foals and adult horses. Relative hepatic mass (as a percentage of body weight) and enzyme activity per gram of hepatic tissue are high in young animals, indicating that the high serum enzyme activities in foals are due partly to a high rate of enzyme production and release.
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PMID:Effect of age on liver enzyme activities in serum of healthy quarter horses. 614 23

Interspecific F1 hybrids of Peromyscus maniculatus (deermice) and P. polionotus (oldfield mice) were backcrossed to P. maniculatus. Backcross progeny were electrophoretically typed for 11 variant protein markers: albumin, transferrin, leucine aminopeptidase, amylase, 6-phosphogluconate dehydrogenase, nucleoside phosphorylase, dipeptidase, tripeptidase, glutamate oxaloacetate transaminase, alcohol dehydrogenase, and sorbitol dehydrogenase. Genetic variation for each protein was attributed to a single autosomal locus. The alcohol dehydrogenase (Adh), salivary amylase (Amy), and albumin (Alb) loci appeared to be linked in the sequence of Adh-11.5 cM-Amy-33.3 cM-Alb. The tripeptidase locus, Pep-2, also may be loosely linked to Alb in this group. Variants at all other loci assorted independently. These and other known linkage relationships in Peromyscus correspond closely to those of the house mouse, Mus musculus. The available evidence in Peromyscus further supports the concept of linkage conservation by natural selection.
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PMID:Linkage relationships among eleven biochemical loci in Peromyscus. 620 Jan 3

The effect of haemolysis on the levels of commonly analysed plasma constituents was investigated in the common marmoset. Results were divided into a) low levels of extra haemolysis (less than 2 g/l plasma haemoglobin) and b) high levels of extra haemolysis (greater than 2 g/l plasma haemoglobin). Mean changes in plasma constituent levels were examined and the correlation with increased haemolysis measured. Large changes in malate dehydrogenase and lactate dehydrogenase were found at low levels of haemolysis. With higher levels of haemolysis there were statistically significant changes in the levels of alanine aminotransferase, isocitrate dehydrogenase, glutathione reductase, bilirubin, aspartate aminotransferase and sorbitol dehydrogenase. The significance of these findings is considered in relation to the interpretation of changes of plasma constituents as indicators of tissue/organ damage.
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PMID:The effect of haemolysis on some clinical chemistry parameters in the marmoset (Callithrix jacchus). 643 Nov 86

Pretreatment with Zn is known to produce tolerance to several toxic effects of Cd. This study was designed to determine if zinc pretreatment decreased Cd-induced lethality and hepatotoxicity. Rats given 4.0 mg Cd/kg, iv, died within 10 to 20 hr while there was no mortality in rats pretreated with Zn (12 mg Zn/kg, sc, 48 and 24 hr prior to Cd challenge). Ten hr after Cd, plasma aspartate aminotransferase and sorbitol dehydrogenase activities were markedly elevated and extensive histopathologic lesions of the liver were evident in control rats while such injury was not evident in Zn-pretreated rats. To examine the mechanism of this tolerance, distribution of Cd to 14 organs and the subcellular distribution in 6 organs (liver, kidneys, intestines, heart, spleen, and testes) was determined in control and Zn-pretreated rats. Two hours after challenge (3.5 mg Cd/kg, iv, 7 microCi 109Cd/mg Cd), the distribution of Cd to the liver markedly increased after Zn pretreatment without concomitant decreases in other tissues. Zn pretreatment resulted in distribution of more Cd to hepatic cytosol and less associated with endoplasmic reticulum. Gel filtration chromatography indicated that most cytosolic Cd was bound to metallothionein. These data suggest that Zn pretreatment reduces Cd-induced hepatotoxicity which prevents the lethal effects of Cd possibly by altering the hepatic subcellular distribution of Cd.
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PMID:Zinc-induced tolerance to cadmium hepatotoxicity. 674 Jun 79


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