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:2.6.1.2 (alanine aminotransferase)
26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the adult rat kidney, alanine aminotransferase (EC 2.6.1.2), aspartate aminotransferase (EC 2.6.1.1) and D-amino acid oxidase (EC 1.4.3.3) were measured in glomeruli, 4 parts of the proximal tubule, 2 parts of the distal tubule and in patches from the thin limb area and the papilla. These enzymes were measured in more limited parts of the nephron during postnatal development. Adult aspartate aminotransferase activities (percentage of the highest) ranged from 100 in the distal straight segment to 25 in the late part of the proximal straight segment to 10 in the thin limb and papillary area. Alanine aminotransferase (lower by a factor of 100 in absolute terms) was distributed as the mirror image of aspartate aminotransferase within proximal and distal tubules. D-Amino acid oxidase was 850-fold higher in proximal straight segments than in medullary structures. During development alanine aminotransferase increased 6-fold and D-amino acid oxidase, 4.5-fold in proximal straight tubules but aspartate aminotransferase increased in distal straight tubles 8-fold.
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PMID:Distribution of two aminotransferases and D-amino acid oxidase within the nephron of young and adult rats. 3 98

This investigation was undertaken to assess the potential of ingested 1,2-dibromo-3-chloropropane (DBCP) to cause testicular and hepatorenal injury, in light of the paucity of data applicable to risk assessment of DBCP in drinking water. Adult male Sprague-Dawley rats were supplied ad libitum with water containing 0, 5, 50, 100, and 200 ppm DBCP for 64 days. A dose-related decrease in water consumption occurred during the study. The 200-ppm animals drank less than half as much water as controls, consumed less food, and subsequently exhibited significantly lower body weight gain. DBCP ingestion thus was not directly proportional to the level of chemical in the water, although daily and cumulative intake of DCP were concentration dependent. Average daily intake of DBCP for the 64-day exposure period was as follows: 5 ppm = 0.4 mg/kg/day; 50 ppm = 3.3 mg/kg/day; 100 ppm = 5.4 mg/kg/day; 200 ppm = 9.7 mg/kg/day. Blood samples were taken after 2, 4, and 6 weeks of exposure and at the terminal sacrifice and assayed for serum glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase, sorbitol dehydrogenase, and ornithine-carbamyl transferase activities and BUN levels. No evidence of liver damage at any exposure level was indicated by either the clinical chemistry indices or histopathology. Histologic examination revealed an apparent increase in the number of nuclei per renal proximal tubule cross-section in the 200-ppm group, possibly indicative of an increased turnover of proximal tubular cells. A slight, but statistically significant, decrease in absolute testicular weight was manifest in the 200-ppm animals, although the decrease was not significant when testicular weight was calculated as g/100 g body wt. Epididymal sperm counts and serum luteinizing hormone, follicle stimulating hormone, and intratesticular testosterone levels were not altered by any dose of DBCP. A qualitative histopathological examination of the testicular seminiferous epithelium failed to reveal any abnormalities in the spermatogenic process.
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PMID:Assessment in rats of the gonadotoxic and hepatorenal toxic potential of dibromochloropropane (DBCP) in drinking water. 262 Jul 97

Excretion of urinary lactate dehydrogenase (LDH, EC 1.1.1.27), gamma-glutamyltransferase (gamma-GT, EC 2.3.2.2), alkaline phosphatase (ALP, EC 3.1.3.1), alanine aminopeptidase (AAP, EC 3.4.11.-), alanine aminotransferase (GPT, EC 2.6.1.2) and N-acetyl-beta-D-glucosaminidase (NAG, EC 3.2.1.30) was studied following a single i.v. application of 1 mg mercuric chloride/kg body weight or a radio contrast medium (SH H 340 AB) at a dose of 7.5 g iodine/kg body weight in rats. Measurements of urinary enzymes and serum urea nitrogen and creatinine were carried out on the second, third, fourth and ninth days after treatment. Histological examinations of kidneys were performed on day 9. A drastic increase in urinary LDH and moderate increase in gamma-GT, ALP and AAP and a very slight increase in GPT was observed in the first 18-h urine samples after mercuric chloride. This increase in enzymuria was associated with a drastic increase in serum urea nitrogen and creatinine, with a maximum on day 4. The radio contrast medium-treated animals showed a similar but less pronounced pattern of urinary enzymes excretion and only a slight increase of serum urea nitrogen on day 2. A good correlation was found between histological findings and enzymuria as well as serum urea nitrogen and creatinine. Thus, determination of only some urinary enzymes (LDH and gamma-GT) is valuable in predicting early nephrotoxicity and sufficient for the diagnosis of proximal tubule damage in rats.
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PMID:Value of enzyme determinations in urine for the diagnosis of nephrotoxicity in rats. 287 61

Diethyl 4-(benzothiazol-2-yl)benzylphosphonate (KB-944), a new Ca-antagonist, in the dose range of 25--200 mg/kg/day, was orally administered to Jcl:SD rats for five consecutive weeks and the following results were obtained. Neither death nor inhibition of body weight gain nor any toxic symptoms of the drug were noted in rats but an increase in water intake was found in the rats treated with over 100 mg/kg/day of KB-944. In plasma there was a decrease in alkaline phosphatase activity, creatinine level and cholinesterase activity and an increase in GPT activity and total cholesterol level in rats given a higher dosage of the drug. Weight gain of the liver, kidneys, heart, adrenals and ovaries, and degeneration in the epithelium of the renal proximal tubule were observed. However, none of these changes were serious and the maximum non-toxic dose of KB-944 was 25 mg/kg/day.
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PMID:1-month subacute oral toxicity study of KB-944, a new calcium antagonist, in rats. 689 Aug 29

Urinary biochemical indicators of renal injury were examined in 84 male and 38 female ferrochromium-producing workers exposed to water-soluble chromium compounds [Cr(VI)]. The indicators examined included urinary chromium (U-Cr), alkaline phosphatase (ALP), gamma-glutamyl transferase (gamma-GT), glutamic-oxalacetic and glutamic-pyruvic transaminases (GOT & GPT), lactate dehydrogenase (LDH), N-acetyl-beta-D-glucosaminidase (NAG), total protein (TPr) and beta 2-microglobulin (beta 2-MG). The U-Cr levels in the exposed group were approximately 1.8 times that of the control group. Compared to controls, the activities of gamma-GT, NAG, ALP, GOT and LDH in the urine of workers were significantly increased whenever U-Cr concentration exceeded 45 microgram/g creatinine. The activities of gamma-GT, GOT and NAG were elevated in workers employed for longer than ten years. However, no clear dose-response relationships nor time-effect relationships were found. The present results suggest that long-term exposure to water-soluble chromium [Cr(VI)] produces chronic renal injury. The site of the injury appears to mainly involve the proximal tubule. U-Cr concentrations of > 15 microgram/g creatinine can be proposed as a threshold dosage for nephrotoxicity, and gamma-GT, NAG and ALP are early sensitive indicators of the most valuable for evaluating the renal injury.
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PMID:Chromium-induced early changes in renal function among ferrochromium-producing workers. 791 62

This study examined the contribution of biotransformation by the mixed function oxidase system on hepatic and renal toxicity of 1,2-dichlorobenzene (1,2-DCB). Male Fischer 344 (F344) rats (190-250 g) were pretreated with phenobarbital (PB), beta-naphthoflavone (BNF), pyridine (PYR), piperonyl butoxide (PiBx) or vehicle prior to the administration of 2 or 3 mmol/kg of 1,2-DCB. Pair-fed control animals were treated with corn oil, (1 ml/kg). Plasma alanine amino-transaminase (ALT/GPT) was increased in a dose-dependent manner by 1,2-DCB. Pretreatment with PB, BNF or PB pretreatment prior to 1,2-DCB administration increased hepatic toxicity within 24 h. Toxicity was characterized by increased ALT/GPT activity and increased liver weight. Acute administration of 1,2-DCB produced renal alterations within 24 h. Renal toxicity was characterized by altered blood urea nitrogen (BUN) concentration and decreased renal cortical slice accumulation of p-aminohippurate (PAH) 24 h after injection of 3 mmol/kg 1,2-DCB. Pretreatment with PB, BNF or PYR increased the renal toxicity of 2 and 3 mmol/kg 1,2-DCB. Conversely, pretreatment with PiBx to inhibit P450 activity slightly decreased the hepatic and renal toxicity of 1,2-DCB. These results establish that the kidney was a target organ for 1,2-DCB toxicity and that the proximal tubule was a site of damage. Additionally, these studies indicate induction of P450 isozymes increased the hepatic and renal toxicity of 1,2-DCB. Further studies are needed to examine the specific role of P450 in generation of toxicity.
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PMID:Modification of P450 activity and its effect on 1,2-dichlorobenzene toxicity in Fischer 344 rats. 831 47

Present package labeling for sevoflurane recommends the use of fresh gas flow rates of 2 L/min or more when delivering anesthesia with sevoflurane. This recommendation resulted from a concern about the potential nephrotoxicity of a degradation product of sevoflurane, "Compound A," produced by the action of carbon dioxide absorbents on sevoflurane. To assess the adequacy of this recommendation, we compared the nephrotoxicity of 8 h of 1.25 minimum alveolar anesthetic concentration (MAC) sevoflurane (n = 10) versus desflurane (n = 9) in fluid-restricted (i.e., nothing by mouth overnight) volunteers when the anesthetic was given in a standard circle absorber anesthetic system at 2 L/min. Subjects were tested for markers of renal injury (urinary albumin, glucose, alpha-glutathione-S-transferase [GST], and pi-GST; and serum creatinine and blood urea nitrogen [BUN]) before and 1, 2, 3, and/or 5-7 days after anesthesia. Desflurane did not produce renal injury. Rebreathing of sevoflurane produced average inspired concentrations of Compound A of 41 +/- 3 ppm (mean +/- SD). Sevoflurane was associated with transient injury to: 1) the glomerulus, as revealed by postanesthetic albuminuria; 2) the proximal tubule, as revealed by postanesthetic glucosuria and increased urinary alpha-GST; and 3) the distal tubule, as revealed by postanesthetic increased urinary pi-GST. These effects varied greatly (e.g., on postanesthesia Day 3, the 24-h albumin excretion was < 0.03 g (normal) for one volunteer; 0.03-1 g for five others; 1-2 g for two others; 2.1 g for one volunteer; and 4.4 g for another volunteer). Neither anesthetic affected serum creatinine or BUN, nor changed the ability of the kidney to concentrate urine in response to vasopressin, 5 U/70 kg subcutaneously (i.e., these measures failed to reveal the injury produced). In addition, sevoflurane, but not desflurane, caused small postanesthetic increases in serum alanine aminotransferase (ALT), suggesting mild, transient hepatic injury.
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PMID:Nephrotoxicity of sevoflurane versus desflurane anesthesia in volunteers. 945 67

Tubulointerstitial disease, a prominent phenomenon in diabetic nephropathy, correlates with decline in renal function. The underlying pathogenic link between chronic hyperglycemia and the development of tubulointerstitial injury has not been fully elucidated, but myofibroblast formation represents a key step in the development of tubulointerstitial fibrosis. RAGE, the receptor for advanced glycation end products (AGEs), induces the expression of TGF-beta and other cytokines that are proposed to mediate the transdifferentiation of epithelial cells to form myofibroblasts. Here we report specific binding of (125)I-AGE-BSA to cell membranes prepared from a rat proximal tubule cell line and show that the binding site was RAGE. AGE exposure induced dose-dependent epithelial-myofibroblast transdifferentiation determined by morphological changes, de novo alpha smooth-muscle actin expression, and loss of epithelial E-cadherin staining. These effects could be blocked with neutralizing Ab's to RAGE or to TGF-beta. Transdifferentiation was also apparent in the proximal tubules of diabetic rats and in a renal biopsy from a patient with type 1 diabetes. The AGE cross-link breaker, phenyl-4,5-dimethylthiazolium bromide (ALT 711) reduced transdifferentiation in diabetic rats in association with reduced tubular AGE and TGF-beta expression. This study provides a novel mechanism to explain the development of tubulointerstitial disease in diabetic nephropathy and provides a new treatment target.
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PMID:Advanced glycation end products cause epithelial-myofibroblast transdifferentiation via the receptor for advanced glycation end products (RAGE). 1174 69

Cephaloridine, which accumulates in the renal proximal tubule, is a model compound used for studying the toxicity of antibiotics towards this nephron segment. Several studies have demonstrated that cephaloridine alters renal intermediary and energy metabolism, but the mechanism by which this compound interferes with renal metabolic pathways remains incompletely understood. In an attempt to improve our knowledge in this field, we have studied the influence of cephaloridine on the synthesis of glutamine, which represents a key metabolic process involving several important enzymatic steps in the rabbit kidney. For this, suspensions of rabbit renal proximal tubules were incubated for 90 and 180 min in the presence of 5 mM alanine, an important glutamine precursor, both in the absence and the presence of 10 mM cephaloridine. Glutamate accumulation and glutamine synthesis were found to be inhibited by cephaloridine after 90 and 180 min of incubation, and cephaloridine accumulation in the renal proximal cells occurred in a time-dependent manner. The renal proximal tubule activities of alanine aminotransferase and glutamate dehydrogenase, which initiates alanine removal and releases the ammonia needed for glutamine synthesis, respectively, were inhibited to a significant degree and in a concentration-dependent manner by cephaloridine concentrations in the range found to accumulate in the renal proximal cells. Citrate synthase and glutamine synthetase activities were also inhibited by cephaloridine, but to a much lesser extent. The above enzymatic activities were not found to be inhibited when they were measured after successive dilutions of renal proximal tubules incubated for 180 min in the presence of 5 mM alanine and 10 mM cephaloridine. When microdissected segments (S1-S3) of rabbit renal proximal tubules were incubated for 180 min with 5 mM alanine with and without 5 and 10 mM cephaloridine, glutamate accumulation and glutamine synthesis were also inhibited in the three renal proximal segments studied; the latter cephaloridine-induced inhibitions observed were concentration-dependent except for glutamine in the S3 segment. These results are consistent with the view that cephaloridine accumulates and is toxic along the entire rabbit renal proximal tubule. They also demonstrate that cephaloridine interferes in a concentration-dependent and reversible manner mainly with alanine aminotransferase and glutamate dehydrogenase, which are therefore newly-identified targets of the toxic effects of cephaloridine in the rabbit renal proximal tubule.
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PMID:Identification of novel targets of cephaloridine in rabbit renal proximal tubules synthesizing glutamine from alanine. 1599 Oct 25

Cerebral edema is a feared complication to acute liver failure (ALF), but the pathogenesis is still poorly understood. The water channels Aquaporin-1 (Aqp1) and -4 (Aqp4) has been associated with brain edema formation in several neuropathological conditions, indicating a possible role of Aqp1 and/or Aqp4 in ALF mediated brain edema. We induced acute liver injury and hyperammonemia in mice, to evaluate brain edema formation and the parallel expression of Aqp1 and Aqp4 in ALF. Liver injury and hyperammonemia were induced by +D-galactosamine (GLN) plus lipopolysaccharide (LPS) intraperitoneally and intravenous ammonia-acetate (NH(4)(+)), the GLN+LPS+NH(4)(+) group. The vehicle control group (CONTROL) was treated with NaCl and phosphate-buffered saline. The GLN+LPS+NH(4)(+) group showed significantly elevated p-alanine aminotransferase, p-INR and p-ammonium vs. CONTROL (p < 0.001). Cortical brain water content was significantly elevated in the GLN+LPS+NH(4)(+) group vs. CONTROL, mean (SEM) 80.8(0.3) vs 80.0(0.1) % (p < 0.05). Western blot of membrane enriched cortical brain tissue showed significantly upregulation of Aqp4 in the GLN+LPS+NH(4)(+) group vs. CONTROL, mean AU (SEM) 100775(14820) vs. 58857(6266) (p < 0.05), and stationary levels for Aqp1. Aqp1 and Aqp4 mRNA were stationary. This study indicates that Aqp4, but not Aqp1, may be of importance in the pathogenesis of cortical brain edema in mice with ALF.
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PMID:Brain expression of the water channels aquaporin-1 and -4 in mice with acute liver injury, hyperammonemia and brain edema. 2093 28


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