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:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of co-administration of diethylnitrosamine (DEN) and Clophen A 50, a commercial mixture of polychlorinated biphenyls (PCB), on pre-neoplastic enzyme-altered islands in livers of female Sprague-Dawley rats was studied. The islands were identified by the loss of adenosine-5'-triphosphatase (ATPase), emergence of gamma-glutamyltranspeptidase (GGTase) and glycogen storage after fasting. DEN was given p.o. (0.4 or 4 mg/kg body wt respectively) twice a week for 11 consecutive weeks. Clophen A 50 (1 or 5 mg/kg body wt respectively) was given alternatively three times a week for 11 weeks. Four groups of rats each received either DEN or PCBs in the respective doses. Control animals were treated with the vehicle or remained untreated. All animals were killed at week 12. In rats treated with 4 mg DEN/kg body wt approximately 80 ATPase-deficient islands/cm2 were observed. Additional treatment with Clophen A 50 enhanced the island number 3-fold. Treatment with 0.4 mg/kg body wt DEN induced 17 islands/cm2. Additional application of Clophen A 50 enhanced the island number approximately 3-fold. The total island area was enhanced to the same extent in both groups. The island incidence in PCB-treated rats and controls was below 1/cm2 with all markers tested. The results indicate that PCBs may exhibit a co-carcinogenic activity.
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PMID:Enhancing effect of co-administration of polychlorinated biphenyls and diethylnitrosamine on enzyme-altered islands induced by diethylnitrosamine in rat liver. 287 10

Preneoplastic liver lesions were produced in female Wistar rats by low doses of aflatoxin B1 (Model 1: administration of 37.5 micrograms/kg 12 and 24 h after partial hepatectomy; Model 2: continuous application of 3.5 micrograms/kg in tap water daily for 28 days with partial hepatectomy after 14 days. The animals then received sodium phenobarbital, 0.1% in tap water, for 180 to 400 days). In both models numerous altered hepatic foci (AHF) and hyperplastic nodules (HN) were detected enzyme histochemically by their negative ATPase and positive gamma-glutamyltranspeptidase reactions. Immunohistochemically these lesions were also UDP-glucuronyltransferase positive. Increased UDP-glucuronyltransferase adds to permanent alterations of a number of drug metabolizing enzymes observed in a variety of different tumor models. These alterations are responsible for the toxin-resistant phenotype (Faber 1984b). Increased gamma-glutamyltranspeptidase was detected both enzyme histochemically and immunohistochemically; whereas gamma-glutamyltranspeptidase activity was present in both AHF/HN and in periportal areas by enzyme histochemistry, the immunohistochemical method selectively stained gamma-glutamyltranspeptidase in AHF and HN. Immunohistochemically detectable UDP-glucuronyltransferase and gamma-glutamyltranspeptidase are markers of putative precancerous liver lesions which may be useful in the analysis of the prestages of liver carcinogenesis.
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PMID:Increased UDP-glucuronyltransferase and gamma-glutamyltranspeptidase in enzyme-altered rat liver lesions produced by low doses of aflatoxin B1. 287 48

Pectin-induced changes in microflora have been shown to elevate the covalent binding of 2,6-dinitrotoluene (2,6-DNT)-related materials to total rat hepatic macromolecules. Therefore, the effect of diets varying in pectin content on the induction of foci and hepatic tumors induced by 2,6-DNT was studied in male F344 rats. 2,6-DNT (3.0-3.5 and 0.6-0.7 mg/kg/day) was incorporated into NIH-07 (NIH), an open formula cereal-based diet high in pectin content, AIN-76A (AIN), a purified pectin-free diet, or AIN-76A supplemented with 5% pectin (AP). Hepatic foci were scored after histochemical staining for gamma-glutamyl transpeptidase (GGT), canalicular adenosine triphosphatase or glucose-6-phosphatase following administration of test diets for 3, 6 and 12 months. The number of foci per cm3 of liver increased in a dose- and time-department manner following incorporation of 2,6-DNT into test diets with NIH greater than AP greater than AIN. In the NIH diet, 2,6-DNT did not alter the phenotypic distribution of foci. Animals fed control or 2,6-DNT-containing AIN and AP diets had few or no GGT foci throughout the study. Hepatocellular carcinomas and neoplastic nodules were observed only in rats fed NIH containing 2,6-DNT. The concentrations of 2,6-DNT-related material covalently bound to hepatic macromolecules after a single oral dose of radiolabeled 2,6-DNT given after 12 months on the diets increased in control rats and in rats receiving low dose 2,6-DNT in the diet with AIN less than AP less than NIH. These studies show that the carcinogenicity of 2,6-DNT differs depending on whether rats are fed an NIH or AIN (+/- pectin) diet. The results suggest that diet-induced alterations in the covalent binding of 2,6-DNT are not the sole factor in determining the carcinogenic response to 2,6-DNT. Furthermore, unidentified contaminants in cereal-based diets may influence foci and tumor production in rat liver during carcinogen treatment.
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PMID:The effect of diet on 2,6-dinitrotoluene hepatocarcinogenesis. 287 86

F344 Male rats weighting between 90 and 110 gm were given 90 ppm diethylnitrosamine in their drinking water for 5 weeks. Seven weeks after the administration of carcinogen was completed, the rats were sacrificed and sections of their livers were embedded in methacrylate. Serial sections 2 or 4 micron in thickness demonstrated the presence of gamma-glutamyl transpeptidase, acid phosphatase, adenosine triphosphatase, aldehyde dehydrogenase, alkaline phosphatase, alpha-naphthyl butyrate esterase, DT diaphorase, glucose-6-phosphate dehydrogenase, and 5'-nucleotidase activity and glycogen. The use of 4-micron sections of methacrylate-embedded tissue allows the evaluation of many more phenotypic markers in serial sections than is currently possible with frozen sections.
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PMID:Examination of enzyme-altered foci with gamma-glutamyl transpeptidase, aldehyde dehydrogenase, glucose-6-phosphate dehydrogenase, and other markers in methacrylate-embedded liver. 287 68

Two-micrometer sections of methacrylate-embedded kidney were used to investigate the enzymatic activities of mouse kidney where the proximal tubule and Bowman's capsule from the same corpuscle were viewed in the same section. Alkaline phosphatase, acid phosphatase, 5'-nucleotidase, gamma-glutamyl transpeptidase, N-acetyl-beta-glucosaminidase, leucine aminopeptidase, alpha-naphthyl butyrate esterase, and adenosine triphosphatase activities were observed in the proximal tubule, but only 5'-nucleotidase, alpha-naphthyl butyrate esterase, and alkaline phosphatase were observed in the squamous portion of the parietal epithelium of Bowman's capsule. The use of methacrylate-embedded tissue allowed more precise localization of enzymatic activity than is possible with most frozen sections. This may provide interesting applications not only for characterization of kidney diseases but also for characterization of other normal and abnormal tissues.
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PMID:Enzymatic histochemistry of mouse kidney in plastic. 288 Aug 90

[14C]Glutamine uptake in a crude synaptosomal (P2) fraction, (representing the sum of [14C]glutamine accumulated and [14C]glutamate formed by hydrolysis), is distinct from glutamate uptake. Glutamine uptake is Na+-independent and unaffected by the Na+-K+-ATPase inhibitor ouabain, whereas glutamate uptake is Na+-dependent and inhibited by ouabain. The uptake of both glutamine and glutamate is unaffected by the gamma-glutamyltransferase inhibitor, Acivicin. This indicates that glutamine uptake is not mediated by a carrier, as distinct from that of glutamate, and also not linked to gamma-glutamyl-transferase. Na+ affects the distribution of glutamine-derived glutamate by increasing the synaptosomal content and reducing that of the medium. When glutamate release from synaptosomes preloaded with [14C]glutamate is measured by superfusion technique in order to prevent reuptake, Na+ has been found to inhibit release in a non-depolarizing medium (Ringer buffer with no Ca2+) of the [14C]glutamate as well as of endogenous glutamate. The specific activity of the [14C]glutamine-derived glutamate in the incubation medium is much higher than that in the synaptosomes, indicating that there exists a readily releasable pool of newly formed glutamate in addition to another pool. The latter glutamate pool is partially reduced by Na+.
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PMID:Uptake and release for glutamine and glutamate in a crude synaptosomal fraction from rat brain. 288 93

The nasal passages are anatomically complex, and while there have been a number of descriptions of nasal structure in many species, there is very little information available on the distribution of enzymes in the nasal mucosa. In rodents, this delicate mucosa is the first site within the respiratory tract to be exposed during inhalation toxicology studies designed to assess human risks from such exposures. However, the nasal mucosa presents problems for histologic preparation because it is encased in brittle bones. Because of recent interest in the nose as a target site, and findings from biochemical studies which indicate that the nose is very active metabolically, studies were carried out to determine the value of cold glycol methacrylate (GMA) processing for localization of nasal enzymes. For these studies, liver and kidney were used as positive controls. Published histochemical procedures for acid and alkaline phosphatase, adenosine triphosphatase, glucose-6-phosphatase, gamma-glutamyl transpeptidase, and naphthyl butyrate esterase were applied, with modifications, to undecalcified nasal passages of Fisher-344 rats. Frozen sections exhibited excellent enzyme preservation but very poor morphology, while GMA gave good enzyme preservation and excellent morphology. For GMA, acetone fixation generally resulted in the best preservation of enzyme activity. It was concluded that cold GMA processing provides a useful approach to studies of nasal enzyme distribution and that this technique of value for inhalation toxicology studies. Details of enzyme distribution in the squamous, respiratory, and olfactory epithelia, associated glands, and other structures of the nose of the rat are described and discussed.
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PMID:Enzyme histochemistry of the rat nasal mucosa embedded in cold glycol methacrylate. 288 3

Female F344/N rats were initiated with DEN (10 mg/kg) 24 h after a 70% partial hepatectomy. Groups of 10 rats were fed (a) AIN, group-1; (b) PD, group-2; or (c) NIH, group-3, for 1 week after initiation and were then fed NIH plus the promoting agent PB at a level of 0.05% in the diets for 6 months. Other groups were fed NIH for 1 week after initiation and then NIH without PB (group-4), AIN + PB (group-5), AIN without PB (group-6), PD + PB (group-7), or PD without PB (group-8) for 6 months. The numbers and volume percentages of AHF were quantified by stereologic methods from frozen serial sections, stained consecutively for GGT, ATPase, and G6Pase. For the groups fed different diets during the 1st week after initiation, the numbers and volume of AHF were significantly greater in group-2 than in groups 1 or 3. The numbers of AHF were significantly less in group-3 than in group-1. The numbers and volume of AHF were significantly greater in groups fed PB during the promotion phase, except in the case of group-7, whose focal volume did not differ from groups 6 or 8. Group-3 had significantly greater numbers of AHF than groups 5 and 7. These findings can be explained by the hypothesis that the NIH diet contained factors that acted synergistically with PB to enhance tumor promotion. The mean focal volume of both GGT positive and ATPase negative foci was significantly greater in group-5 than in all other groups; this indicates that the AIN + PB regimen selectively promoted the growth of a subpopulation of AHF. These findings show that alterations in the composition of diets fed during hepatocarcinogenesis significantly alter the effects of specific chemical agents acting during the stages of initiation and promotion in hepatocarcinogenesis.
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PMID:Dietary effects on initiation and promotion of hepatocarcinogenesis in rat. 289 12

Formation of the N-(deoxyguanosin-8-yl)-aminofluorene adduct was studied in enzyme-altered foci induced by four different liver carcinogenesis models. Foci were detected and scored for enzyme phenotype by a computer-aided image overlay technique. Localization of the enzymes gamma-glutamyl transpeptidase, canalicular ATPase and glucose-6-phosphatase was performed by enzyme histochemistry, allowing identification of foci of seven different phenotypes. Patterns of foci obtained by image overlay were compared to in situ 2-acetylaminofluorene--DNA adduct distribution obtained by immunofluorescence. Foci were induced by the following models: (1) chronic feeding of 0.02% 2-acetylaminofluorene (2-AAF) for 8 weeks; (2) intubation of diethylnitrosamine (DEN) (10 mg/kg) 24 h after a 70% partial hepatectomy (PH), followed 8 weeks later by a diet containing 0.05% phenobarbital for 9 months; (3) intubation of DEN (10 mg/kg) 24 h after PH, followed by a diet containing 0.01% ciprofibrate for 5 months, and after an additional 4 months a diet containing 0.05% phenobarbital for 2 months; (4) maintenance for 7.5, 16.5 or 19.5 months after transplantation of DEN/2-AAF/PH ('Solt-Farber' protocol) donor liver cells into host rats receiving a brief 2-AAF/PH selective regimen then no further treatment until sacrifice. To test the capacity of both foci and morphologically normal livers to form DNA adducts, the animals in models 2-4 received a diet containing 0.02% 2-AAF for 5 or 6 days before sacrifice. In all of the enzyme-altered foci identified in models 1-3 there were no DNA adducts visible by immunofluorescence. Scattered groups of positive cells were occasionally seen in the otherwise dark foci induced by model 4. For technical reasons some enzyme-altered foci were not identifiable on the fluorescence-stained slides. In liver serial sections from rats in models 1-4, there were 75, 304, 125 and 68 enzyme-altered foci of seven different phenotypes which were identified as AF-DNA negative. In models 1 and 4 there were some additional adduct-negative foci not associated with any of the seven identified focus phenotypes. These studies demonstrate that loss of the ability to form DNA adducts in hepatic enzyme-altered foci is a common and very early biochemical adaptation to xenobiotic exposure in different hepatocarcinogenesis models. This adaptation also is retained by the majority of foci in later stages of hepatocarcinogenesis.
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PMID:Lack of acetylaminofluorene--DNA adduct formation in enzyme-altered foci of rat liver. 289 93

Isolated rat hepatocytes maintained in primary culture on gas permeable membrane for 20 h form monolayers and establish at their cell borders a network of canaliculi (approximate diameter 3.5 micron). In the presence of the known choleretic bile acid dehydrocholate, dilation of canaliculi occurs. When nonfluorescent carboxyfluorescein diacetate ester is added to the culture medium, fluorescent carboxyfluorescein appears in the intracanalicular space. In the dilated state, fluid containing the fluorescent compound could be collected from the canaliculi by puncture with a micropipette. The intracanalicular space shows a negative electrical potential difference of 31 mV in reference to the bath solution and is 13.5 mV more positive with reference to recordings from the cytosol of cultured rat hepatocytes. Cultured rat hepatocytes grown on gas permeable membrane are energetically stable over 3 d. On Day 4, ATP levels increase markedly, whereas Na+-K+-ATPase activity declines. Ionic composition of hepatocytes, as measured by electronprobe element analysis on cryosection samples, does not change markedly during monolayer formation. With formation of bile canaliculi, the activity of alkaline phosphatase rapidly increases within 24 h and is stable for the next 3 d. Within that time the activity of gamma-glutamyltranspeptidase, however, increases steadily, reaching a 1.6-fold higher activity than freshly isolated hepatocytes. Bile acids appear in the culture supernatant after 1 d. When unconjugated [14C]cholic acid is added to the cultures the supernatant contains also [14C]tauro- and [14C]glycocholic acid, indicating the preservation of conjugation capacity in these cultures. Total bile acid concentrations in the supernatant increase from 5 to 26 microM on Day 4. The cultures do not secrete alpha-fetoprotein. Monolayer cultures of hepatocytes in the presence of choleretic bile acids seem to be a suitable model system to collect and to analyze the composition of primary bile. In conjunction with the electrical parameters, it is possible to describe directly properties of bile secretion at the canalicular pole of the intact hepatocyte.
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PMID:Primary liver cell cultures grown on gas permeable membrane as source for the collection of primary bile. 289 70


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