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:3.4.24.3 (collagenase)
18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A chromosomal analysis was performed on two cell lines which were derived from the liver of two rats exposed to diethylnitrosamine in vivo. The cells were obtained by collagenase perfusion of the liver at an early stage of development of ATPase-deficient putative preneoplastic populations, and propagated from foci of epithelial cells which started growth in vitro. Cell line CL 38 proved to be tumorigenic after transplantation into nude mice, giving rise to hepatocellular carcinomas and metastases. Cell line CL 44 was nontumorigenic after transplantation into nude mice and was therefore considered preneoplastic. The diploid nontumorigenic line CL 44, with a modal number of 42 chromosomes, showed a deletion of chromosome 1 and a translocation of chromosomes 3 and 14 [t(3q12;14q21)]. The hyperdiploid neoplastic cell line CL 38 has a modal chromosome number of 52 and showed tri- or tetrasomy of chromosomes 3, 7, 9, 11, and 12 and a marker chromosome that might have originated from aberrant chromosome 1. One or two homologues of chromosome 3 showed terminal deletions (q42, q41, or q35). In both cell lines rearrangements of chromosome 11 were observed [rob(11q;?) or +11 or -11 or del(11)(q12)]. Some of these karyotype abnormalities are located on the same chromosome as described for transplantable hepatomas and for other chemically induced tumors of the rat.
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PMID:Chromosomal analysis of a diethylnitrosamine-induced tumorigenic and a nontumorigenic rat liver cell line. 272 Jun 63

We have recently demonstrated that dopamine (DA) inhibits Na,K-ATPase in single proximal tubule (PCT) segments dissected from previously collagenase perfused rat kidney. The aim of the present study was to ascertain whether this effect was directly mediated by DA or if DA was the precursor of an inhibitor. When PCT segments were incubated with L-DOPA, Na,K-ATPase was significantly lower than in vehicle incubated tubules. Inhibition of dopa decarboxylase abolished the effect of L-DOPA on Na,K-ATPase activity. The metabolites of DA, 3, 4-dihydroxphenyl acetic acid (DPAC) and homovanillic acid (HVA) both inhibited Na,K-ATPase activity in doses higher than 10(-6) M. Both HVA and DPAC 10(-4) M caused approximately 35% inhibition. Dopamine inhibited Na,K-ATPase activity even in a dose as low as 10(-7) M. Maximal inhibition (greater than 60%) was found with DA-5 M. Na,K-ATPase activity was significantly lower in tubules exposed to DA 10(-4) and 10(-5) M than in tubules exposed to DPAC or HVA 10(-4) and 10(-5) M. Dopamine produced in proximal tubule cells from L-DOPA, is an active inhibitor of the Na,K-pump in these cells. The DA metabolites DPAC and HVA are less potent Na,K-pump-inhibitors.
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PMID:Effect of L-DOPA, dopamine, dihydroxyphenyl acetic acid and homovanillic acid on Na,K-ATPase activity in rat proximal tubule segments. 282 Jan 98

The aim of this study was to develop an in vitro system in which we could study the causal relationship between short-term stimulation of Na+,K+-ATPase in the collecting tubule by aldosterone on the one hand and protein synthesis and changes in intracellular Na+ concentration on the other hand. Previous in vivo studies suggested that triiodothyronine might facilitate aldosterone-induced stimulation of Na+,K+-ATPase. Results show that when segments of cortical collecting tubules microdissected from collagenase-treated kidneys of adrenalectomized rats were incubated for 3 hr in the presence of either 10(-8) M aldosterone or 10(-8) M triiodothyronine alone Na+,K+-ATPase activity was not altered, whereas the addition of both hormones markedly stimulated the activity and the number of catalytic sites of Na+,K+-ATPase. This stimulation was abolished by actinomycin D and cycloheximide, whereas it was not altered in the absence of extracellular sodium or in the presence of the luminal Na+-channel blocker amiloride. Thus, triiodothyronine facilitates the in vitro induction of Na+,K+-ATPase synthesis by aldosterone. Aldosterone action on Na+,K+-ATPase is independent of Na+ availability.
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PMID:Sodium-independent in vitro induction of Na+,K+-ATPase by aldosterone in renal target cells: permissive effect of triiodothyronine. 283 Jun 27

Sequential carcinogen treatment (diethylnitrosamine/partial hepatectomy followed by 2-acetylaminofluorene (2-AAF] induced multiple hepatocarcinomas in rats with 100% certainty within a year. Enzyme-altered lesions, i.e. gamma-glutamyltranspeptidase (GGT)-positive and/or ATPase-negative cell foci, were numerous already at 8 weeks, and suspensions of purified hepatocytes isolated (by collagenase perfusion) at this time contained 30-40% GGT-positive cells. These hepatocyte suspensions were markedly deficient with respect to autophagic protein degradation (in comparison with cell suspensions from normal rats), and the cells lost less protein and survived much better than normal hepatocytes in culture under conditions of amino acid deprivation (which activates the autophagic mechanism). The anabolic advantage of reduced autophagy may possibly contribute to the selective outgrowth of preneoplastic cells during the earliest stage of liver carcinogenesis. Inclusion of the autophagy inhibitor 3-methyladenine in the culture medium elevated the survival of normal hepatocytes up to the level seen with hepatocytes from carcinogen-treated animals, suggesting that protection of normal cells by autophagy suppression may be a potentially interesting therapeutic principle.
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PMID:Reduced autophagic activity, improved protein balance and enhanced in vitro survival of hepatocytes isolated from carcinogen-treated rats. 285 48

Preparations of distinct nephron segments were obtained from dog kidneys by collagenase treatment. Four morphologically different tissues were isolated: glomeruli, proximal tubules, thick ascending limbs, and papillary collecting ducts. Each segment possessed a characteristic assay of membrane-bound and cytoplasmic enzymes. Specific metabolic characteristics also were found: gluconeogenesis and ammoniagenesis in proximal tubules, glycolytic aerobic metabolism in thick ascending limbs, and glycolytic anaerobic metabolism in papillary collecting ducts. The assay of Na+ -K+ ATPase, H+ -ATPase, and Ca2+ -ATPase activities in these nephron segments demonstrated a specific enrichment of Na+ -K+ ATPase in thick ascending limbs, and of H+ -ATPase in proximal tubules and papillary collecting ducts. Tubular respiration in the absence or presence of ouabain, 1,3-dicyclohexylcarbodiimide, or furosemide demonstrated that the respiration of each segment could be correlated to the activity of specific ion motive ATPases. Furthermore, a tight coupling between ion transport, ATP turnover, and substrate oxidation was demonstrated. These isolated tubular structures are thus viable and capable of transepithelial transport. Our preparation provides large amounts of defined population of tubules and are thus useful for the study of biochemical and functional heterogeneity along the nephron.
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PMID:Characterization and metabolism of canine proximal tubules, thick ascending limbs, and collecting ducts in suspension. 297 51

Retinal pigment epithelium plasma membranes have been isolated by differential and density gradient centrifugation of glass-bead-bound, collagenase-treated cells. Electron microscopic evidence indicates that the glass-bead-bound cells were devoid of red blood cells, rod outer segments and other ocular cell contaminants. The plasma membranes were recovered in 4-6 micrograms/eye yields and purified 10-fold by 5'-nucleotidase and alkaline phosphodiesterase I, and 6.5-fold by (Na+ + K+)-ATPase. Plasma membrane purity as measured by covalent labeling of the epithelial cell plasma membrane proteins with p-(diazonium) benzene[32S]sulfonic acid was 8-19-fold. In purified plasma membranes contamination by mitochondria was undetectable and lysosomal contamination reduced 100-fold, while endoplasmic reticulum was 2-fold enriched. SDS-polyacrylamide gel electrophoresis of the plasma membrane proteins revealed 23-26 major bands by Coomassie blue staining and 12-16 major bands by radioactive labeling. The plasma membranes exhibited a 3-fold lower concentration of docosahexaenoic acid, a 3-fold higher cholesterol/phosphate ratio, and were 10-fold enriched in cholesterol per micrograms protein when compared to the whole cell fraction. Retinal epithelial plasma membranes contain an average of 1 mol cholesterol per mol of lipid phosphorus, a high palmitic acid concentration (39 mol%) and a low concentration of docosahexaenoic acid (2 mol%). The lipid profile of the retinal pigment epithelial plasma membranes indicates that they are typical of plasma membranes from many other cell types and that they appear to be less fluid than total rod outer segment membranes.
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PMID:Isolation of plasma membranes from the bovine retinal pigment epithelium. 298 2

The calcium accumulating ability of mitochondria isolated both from bovine coronary artery and aorta was investigated. Coronary artery and aorta were pretreated with 0.1% collagenase. Cytochrome c oxidase activities of mitochondria isolated from coronary artery and aorta showed 25-fold and 19-fold increases, respectively, as compared with those of each homogenate, whereas NADPH-cytochrome c reductase, potassium-phosphatase and Na+-K+ ATPase activities increased less than 2-fold. This suggests that the isolation procedure is capable of obtaining a subcellular fraction highly enriched with mitochondria. Mitochondrial calcium uptake activity of the coronary artery was approximately 250 nmoles Ca2+/mg protein/10 min, and was markedly depressed with metabolic inhibitors such as NaN3, ruthenium red and 2,4-dinitrophenol. Calcium uptake activity of bovine aortic mitochondria showed similar activity and a similar trend in sensitivity to metabolic inhibitors. By contrast, the onset of the calcium binding reaction of the aortic mitochondria was slower and the azide-sensitivity of the mitochondria to magnesium ATPase activity was lower than those for coronary artery mitochondria. The present study has provided a method for isolation of mitochondria with a high capacity of calcium uptake activity, which may prove meaningful for future physiological and pharmacological evaluation of mitochondrial calcium accumulation in vascular smooth muscle.
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PMID:Calcium accumulating ability of mitochondria from bovine coronary artery. Comparison with aortic mitochondria. 298 75

Although Ismail-Beigi and Edelman demonstrated in 1971 that thyroid hormones control the activity of Na-K-ATPase in the mammalian kidney, the actual site of this regulation inside the organ was not located. We therefore decided to study the relationship between thyroid hormones and Na-K-ATPase activity in individual nephron segments obtained by microdissection of collagenase-treated rabbit kidneys. For this purpose, the changes in the activity and number of catalytic sites of Na-K-ATPase in response to thyroidectomy or triiodothyronine administration were examined. Eight to 12 days after thyroidectomy, Na-K-ATPase activity had dropped by 40 to 80% in the convoluted and straight portions of the proximal tubules, and in the cortical and outer medullary collecting tubules, but not in the thick ascending limbs of Henle's loops or distal convoluted tubules. The apparent number of catalytic sites for Na-K-ATPase, as measured by specific binding of 3H-ouabain, decreased in parallel with Na-K-ATPase activity, and therefore this enzyme's specific activity was not altered. Fourty eight hours after injection of thyroidectomized animals with a single dose of either 100 or 500 micrograms/kg triiodothyronine, Na-K-ATPase activity in target segments was restored to the level measured in control animals. These effects of thyroid hormone were specific for Na-K-ATPase, since the activity of adenylate cyclase, another marker of the basolateral membrane, was not altered by thyroidectomy. The results obtained indicate that triiodothyronine controls Na-K-ATPase activity in specific nephron segments, by altering the number of this enzyme's catalytic sites.
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PMID:Sites of thyroid hormone action on Na-K-ATPase along the rabbit nephron. 299 94

Na-K-ATPase activity was measured in individual pieces of nephron microdissected from collagenase-treated kidneys of jerboas, Jaculus orientalis. Na-K-ATPase activity was high in the distal convoluted tubule, intermediate in the thick ascending limb of the loop of Henle and low in the proximal and collecting tubule. When jerboas were adapted for several weeks to a hydrated diet and excreted a more diluted urine, Na-K-ATPase activity was altered in specific segments of the nephron: 1. In the proximal convoluted tubule, Na-K-ATPase activity decreased, especially in the juxtamedullary nephrons, suggesting that internephron heterogeneity was diminished; 2. In the medullary thick ascending limb, but not in the cortical portion, Na-K-ATPase activity decreased by 30%; 3. Na-K-ATPase was also diminished in the cortical collecting tubules (by 20%) but not in the medullary collecting tubule. Morphometric measurements also indicate that changes in Na-K-ATPase activity observed in the thick ascending limb are correlated to a cell atrophy, whereas in the collecting tubule, they occur independently of any visible morphological alteration. These differences in Na-K-ATPase activity are likely to be secondary to the changes in the plasma concentration of vasopressin previously described during such adaptation and to be involved in the control of water and sodium handling.
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PMID:Effect of water intake on Na-K-ATPase in nephron segments of the desert rodent, Jaculus orientalis. 303 78

Controversy has recently developed over the surface distribution of Na+,K+-ATPase in hepatic parenchymal cells. We have reexamined this issue using several independent techniques. A monoclonal antibody specific for the endodomain of alpha-subunit was used to examine Na+,K+-ATPase distribution at the light and electron microscope levels. When cryostat sections of rat liver were incubated with the monoclonal antibody, followed by either rhodamine or horseradish peroxidase-conjugated goat anti-mouse secondary, fluorescent staining or horseradish peroxidase reaction product was observed at the basolateral surfaces of hepatocytes from the space of Disse to the tight junctions bordering bile canaliculi. No labeling of the canalicular plasma membrane was detected. In contrast, when hepatocytes were dissociated by collagenase digestion, Na+,K+-ATPase alpha-subunit was localized to the entire plasma membrane. Na+,K+-ATPase was quantitated in isolated rat liver plasma membrane fractions by Western blots using a polyclonal antibody against Na+,K+-ATPase alpha-subunit. Plasma membranes from the basolateral domain of hepatocytes possessed essentially all of the cell's estimated Na+,K+-ATPase catalytic activity and contained a 96-kD alpha-subunit band. Canalicular plasma membrane fractions, defined by their enrichment in alkaline phosphatase, 5' nucleotidase, gamma-glutamyl transferase, and leucine aminopeptidase had no detectable Na+,K+-ATPase activity and no alpha-subunit band could be detected in Western blots of these fractions. We conclude that Na+,K+-ATPase is limited to the sinusoidal and lateral domains of hepatocyte plasma membrane in intact liver. This basolateral distribution is consistent with its topology in other ion-transporting epithelia.
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PMID:Localization of Na+,K+-ATPase alpha-subunit to the sinusoidal and lateral but not canalicular membranes of rat hepatocytes. 303 85


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