Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P41181 (collecting duct)
 5,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Histochemical and immuno-histochemical studies on kidney sections of adult rats and rats at different stages of development were carried out to estimate enzyme concentrations in nephron segments. Aminopeptidase and alkaline phosphatase were found from 3 days before birth in proximal tubule cells, aldolase-B and aldolase-A in all the nephron and collecting duct. The concentration of the enzymes remained remarkably constant from the 3rd day after birth onwards, except for aldolase-A in the distal tubule cells. The concentration of aldolase-B was higher than of aldolase-A in the distal tubule cells. The concentration of aldolase-B was higher than of aldolase-A, in glomerula and proximal tubules, that of aldolase-A was higher than that of aldolase-B in the ascending thick part of the Henle loop and in the following parts of the nephron. This implies that the concentration of the enzymes is the limiting factor for the regulation of substrate hydrolysis and that the nephron when formed can function as efficiently as the nephron of the adult rat with respect to these enzymes.
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PMID:Aspects of regulation in kidney at the enzymic level: aldolase isozymes, aminopeptidase and alkaline phosphatase. 79 83

Renal clear cell tubules and clear/acidophilic cell tumors were induced in male Sprague-Dawley rats by 7 weeks oral administration (stop model) of N-nitrosomorpholine (NNM) at a concentration of 12 mg/100 ml in the drinking water. Twelve, 23 and 34 weeks after withdrawal of NNM serial cryostat sections of the kidneys were histochemically analyzed for the following parameters: glucose transporter proteins (GLUT1, GLUT2), glycogen content and the activities of glycogen synthase (SYN), glycogen phosphorylase (PHO), glucose-6-phosphatase (G6Pase), glucose-6-phosphate dehydrogenase (G6PDH), hexokinase (HK), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), pyruvate kinase (PK), succinate dehydrogenase (SDH), malate dehydrogenase (MDH), alkaline phosphatase (ALP), acid phosphatase (ACP) and gamma-glutamyltransferase (GGT). Clear cell (glycogenotic) tubules first appeared at 23 weeks, and clear/acidophilic cell tumors at 34 weeks after withdrawal of the carcinogen. G6Pase, ALP, GGT and GLUT2 were absent in clear cell tubules, clear/acidophilic cell tubules, and clear/acidophilic cell tumors indicating a sequential origin of all these types of lesions from the collecting duct system, in line with previous morphological findings. In comparison to the collecting duct epithelium, glycogenotic tubules demonstrated an increased activity of PHO and reduced activities of glycolytic and mitochondrial enzymes, which were accompanied by a strongly reduced expression of GLUT1. Moderately increased activities of glycolytic and mitochondrial enzymes were observed in the clear cells of clear/acidophilic cell tubules and tumors compared with those in glycogenotic tubules. They had slightly increased activities of the glycolytic enzymes GAPDH and PK compared with normal collecting duct epithelium, while most of them were nearly lacking in GLUT1. Our findings suggest that glycogen storage is not due to an increased uptake of glucose from the blood, but results from a disturbance in intracellular flux of metabolites. The development of clear cell tubules from the normal collecting duct epithelium is accompanied by a markedly decreased expression of GLUT1 along with a reduction in glycolytic and mitochondrial enzymes. This reduction of enzyme activities is replaced by an increase in enzyme activities in clear/acidophilic cell tumors indicating a fundamental shift in carbohydrate metabolism during progression from preneoplastic to neoplastic lesions.
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PMID:Sequential changes in glycogen content, expression of glucose transporters and enzymic patterns during development of clear/acidophilic cell tumors in rat kidney. 147 41

A plasma membrane glycoprotein (gp110) involved in cellular adhesion was studied in Wistar and Fischer rats. For quantitative analysis of the gp110 molecule a sandwich-ELISA was used. High quantities of gp110 were found especially in the liver, small intestine, submandibular gland and lung. The distribution and localization of the gp110 were investigated by immunohistochemistry utilizing soluble complexes of alkaline phosphatase and monoclonal anti-alkaline phosphatase antibodies. Immunoreactivity was present in plasma membranes of vascular endothelial cells of some organs. Furthermore, immunostaining also occurred in plasma membranes of lymphocytes, exocrine gland cells, excretory duct cells, hepatocytes, epithelial cells of the small intestine, kidney and vesicular gland and in the cytoplasm of renal connecting and collecting duct cells. The localization of gp110 in the luminal domain of the plasma membrane at many sites suggests that this glycoprotein is also involved in processes distinct from cell adhesion.
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PMID:Localization of a putative cell adhesion molecule (gp110) in Wistar and Fischer rat tissues. 261 47

The distribution and activities of phosphatases and oxidative enzymes have been determined with the help of histochemical methods in the kidney of the Prussian Carp, a stenohaline freshwater-fish. In addition to fish maintained in freshwater aquaria, a group of the animals used has been adapted to seawater of moderate salinity. The following pattern of enzyme reaction intensities has been observed in the various kidney structures: Strong reactions of alkaline phosphatase in the nephron are confined to the glomerular capillary convolute and the brush border of proximal segments. Equally enzyme activities are observed in the connective tissue sheath of the collecting duct -- archinephric duct system. Acid phosphatase can be detected in all segments of the nephronic tubule, strong activities are found in the proximal segment (P I), in the epithelium of the archinephric duct, and, especially, in the interstitial tissue. ATPase reacts strongly positive in epithelial cells of the distal tubule and the collecting duct -- archinephric duct system. ATPase reactions are inhibited by Ouabain, and therefore can be regarded as reactions of Na--K-ATPase. Mitochondrially bound oxidative enzymes, connected with the citric acid cycle and the respiratory chain, show very strong reaction intensities in the distal tubule and the collecting duct- archinephric duct system, while the glomeruli generally exhibit negative reactions. Lactate -- and malate dehydrogenases are found to react weakly to negatively throughout the whole kidney. Maintenance in seawater does not deeply affect the enzyme pattern of the kidney of the Prussian carp, with exception of some oxidative enzymes, reacting weaker in the distal tubule and the collecting duct-archinephric duct system. In addition, the epithelial cells of the archinephric duct of seawater adapted fish show a marked apical localization of reaction products for these enzymes. Possible relations between enzyme histochemistry and fish kidney physiology are discussed, in connection with comparative aspects of the enzyme histochemistry of the vertebrate kidney. A short review of normal histology and function of the kidney of the Prussian carp is added.
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PMID:[Phosphatases and oxidative enzymes in the kidney of the Prussian carp (Carassius auratus gibelio Bloch) adapted to salt water]. 625 47

The current report presents findings from a comparative histological and histochemical investigation of murine congenital polycystic kidney disease. The studies revealed that the morphological changes are initiated in the developing proximal tubules of the nephron; differences from control sections first become evident at 16 days' gestation. As the disease progresses, obvious changes include hyperplasia and dilation of the tubule, cellular vacuolization, and alterations in the apical cell brush border. Included among the latter changes are decreases in enzyme (alkaline phosphatase) staining and decreases in glycoprotein staining (periodic acid Schiff). All such changes continue until the kidney is markedly cystic and apical cell cytochemical staining is absent. Some cellular vacuolization, assumed to be a normal developmental event, is also seen within the same segment of the proximal tubule at 17 days' gestation through the 1st postnatal day. Dilation of the collecting duct is noted to be a later or secondary change evident after the initial onset of the disease.
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PMID:Development of the embryonic murine kidney in normal and congenital polycystic kidney disease: characterization of a proximal tubular degenerative process as the first observable light microscopic defect. 669 Jul 41

The early effects of lithium on the kidney were studied in rats receiving a moderate daily dose (serum-Li: 0.5 to 0.8 mM per liter) for 3, 7, and 21 days. Enzyme histochemical reactions for acid and alkaline phosphatase, glucose 6-phosphatase, succinate and alpha-glycerophosphate dehydrogenase, and NADH tetrazolium reductase revealed changes confined to distal convoluted tubules and collecting ducts. The distal convoluted were unchanged at 3 days of treatment. At 7 days, a decrease in succinate dehydrogenase and NADH tetrazolium reductase and an increase in alpha-glycerophosphate dehydrogenase were noted. These changes were more conspicuous at 21 days and accompanied by tubular dilation and changes in light microscopic cellular morphology. In the collecting ducts, a cell enlargement and an increase in mitochondrial oxidative enzyme activities began to appear at 3 days, becoming more pronounced at 7 and particularly at 21 days. At 7 and even more at 21 days, a cellular hyperplasia was evident in the collecting ducts, and autoradiography after 3H-thymidine incorporation showed a marked increase in DNA synthesis in the collecting duct cells. The changes observed in the collecting ducts were most pronounced near the limit between the outer and the inner zone of the medulla. In conclusion, the rats developed morphologic changes at 3 to 7 days of treatment. The changes include (1) signs of cellular damage in the distal convoluted tubules and (2) hyperplasia and signs of increased functional activity in the collecting ducts.
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PMID:Early changes in renal distal convoluted tubules and collecting ducts of lithium-treated rats: light microscopy, enzyme histochemistry, and 3H-thymidine autoradiography. 706 26

A 52-week toxicity study by oral gavage administration was performed in Sprague-Dawley rats with nefiracetam (N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl) acetamide, DM-9384, CAS 77191-36-7), a new cognition-enhancing agent, as a part of a safety evaluation program. Dosages of 0 (control), 10, 30, 100 and 300 mg/kg/d were selected for this study. Treatment-related findings were confined to the 300 mg/kg/d level and, to a lesser extent, the 100 and 30 mg/kg/d levels, with the investigations indicating the kidney as the main target organ for toxicity. The microscopic pathology examination of this organ showed papillary epithelial hyperplasia and/or collecting duct epithelial hyperplasia, with cortical scarring and occasional mineralisation in the papilla. Histopathological changes in the liver, centrilobullar hepatocyte enlargement (accompanied by fine vacuolation) and foci/areas of eosinophilic hepatocytes were considered to reflect the induction of drug-metabolising enzymes in the liver. Other tissues showing treatment-related findings included the salivary glands, urinary bladder, spleen, pancreas and adrenals. Additionally, other notable findings included (in the high dosage males only) a decline in body weight (from week 34), lower erythrocytic characteristics and slightly higher plasma urea nitrogen and alkaline phosphatase values. The results in this study, therefore, indicated that the non-toxic effect level was 10 mg/kg/d of nefiracetam.
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PMID:Fifty-two-week oral toxicity study of the new cognition-enhancing agent nefiracetam in rats. 801 94

The M-1 cell line is derived from the mouse cortical collecting duct and displays the low-conductance, highly Na(+)-selective channel activity of the alpha,beta, gamma-heterotrimeric epithelial Na+ channel (ENaC). The short-circuit current (Isc) across M-1 monolayers was 89 +/- 4 microA/cm2, and the transepithelial conductance was 2.1 +/- 0.2 mS/cm2. Isc was abolished by blocking the Na+ pump with ouabain. Both Isc and transepithelial conductance (gT) were inhibited by benzamil > amiloride >> dimethylamiloride. Under our experimental conditions, vasopressin, vasopressin, forskolin, and dibutyryl adenosine 3',5'-cyclic monophosphate (cAMP) had no detectable effects on Isc or gT. Increasing apical Na+ entry with nystatin increased Isc. The possible regulation of the M-1 Na+ channel by cAMP-activated protein kinase A (PKA) was further examined with excised inside-out patches. The open-time probability (Po) was not fixed, displaying substantial variance. Perfusion with ATP itself, with the catalytic subunit of PKA with ATP, or with alkaline phosphatase had no consistent effect on Po, the unitary current, or the kinetics of the M-1 Na+ channel. The data are consistent with the concept that PKA stimulates ENaCs by phosphorylating a site with access to but not within the apical membrane patch during cell-attached and excised-patch studies.
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PMID:Regulation of epithelial Na+ channels from M-1 cortical collecting duct cells. 889 16

Lysosomal degradation of the ganglioside GM2 by human beta-hexosaminidase A requires the presence of the GM2 activator protein as an essential cofactor. Here we demonstrate that GM2 activator mRNA is differentially expressed and mainly localized to the apical part of the epithelial cells of distal renal tubules and the collecting duct. In order to understand the mechanism underlying the regulation of the GM2 activator gene, we analyzed the genomic organization upstream exon 2 as well as the 5'-flanking region. The GM2 activator gene spans about 16.8 kb with a first intron of 6.5 kb, and the transcription start is located at position -96 upstream from the ATG. DNA elements responsible for GM2 activator expression were identified in a PCR-based method of long-distance DNA walking. Sequence analysis revealed a 2.9 kb region upstream of the ATG that contained regulatory elements like CAAT boxes, Sp1 binding sites as well as AP1, and AP2 sites. Transfection experiments in COS-1 cells with a series of chimeras of 5'-stepwise deletion mutants of the GM2 activator gene 5'-flanking region and the secretory alkaline phosphatase (SEAP)-reporter gene indicated that a genomic fragment encompassing -323 to +1 bp had significant promoter activity. EMSA experiments showed that Sp1 and other transcription factors like AP1, AP2 and CCAAT-Box binding proteins are involved in GM2 activator gene regulation.
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PMID:Characterization of regulatory elements in the 5'-flanking region of the GM2 activator gene. 1098 59

The small-conductance K+ channel (SK) in the apical membrane of the cortical-collecting duct (CCD) is regulated by adenosine triphosphate (ATP) and phosphorylation-dephosphorylation processes. When expressed in Xenopus oocytes, ROMK, a cloned K+ channel similar to the native SK channel, can be stimulated by phosphatidylinositol bisphosphate (PIP2), which is produced by phosphoinositide kinases from phosphatidylinositol. However, the effects of PIP2 on SK channel activity are not known. In the present study, we investigated the mechanism by which hydrolyzable ATP prevented run-down of SK channel activity in excised apical patches of principal cells from rat CCD. Channel run-down was significantly delayed by pretreatment with hydrolyzable Mg-ATP, but ATP gamma S and AMP-PNP had no effect. Addition of alkaline phosphatase also resulted in loss of channel activity. After run-down, SK channel activity rapidly increased upon addition of PIP2. Exposure of inside-out patches to phosphoinositide kinase inhibitors (LY294002, quercetin or wortmannin) decreased channel activity by 74% in the presence of Mg-ATP. PIP2 added to excised patches reactivated SK channels in the presence of these phosphoinositide kinase inhibitors. The protein kinase A inhibitor, PKI, reduced channel activity by 36% in the presence of Mg-ATP. PIP2 was also shown to modulate the inhibitory effects of extracellular and cytosolic ATP. We conclude that both ATP-dependent formation of PIP2 through membrane-bound phosphoinositide kinases and phosphorylation of SK by PKA play important roles in modulating SK channel activity.
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PMID:Hydrolyzable ATP and PIP(2) modulate the small-conductance K+ channel in apical membranes of rat cortical-collecting duct (CCD). 1240 74


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