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)

A) The proximal nephron and perinatal regulation of extracellular volume. 1. The glomerular capillary permeability coefficient (Kf) changes mainly because of an increasing capillary hydraulic conductance (Lp) within the autoregulatory range of renal perfusion pressure. 2. Proximal tubule hydrostatic hydraulic conductance and response to transmural protein concentration gradients is high during perinatal adaptation. 3. Proximal tubule paracellular shunt pathways are more important for absorption during differentiation than at maturity. 4. Basolateral membrane area of the single epithelial segment (10(-6) micron2 mm-1) increases and the typical basal labyrinth architecture develops. 5. The activity of the transport enzyme Na-K-ATPase increases in parallel to the basolateral membrane area to result in a constant number of enzyme sites during normal ontogeny. B) The distal nephron and perinatal regulation of extracellular osmotic activity. 6. Inner medullary urea content increases at osmotic equilibrium between interstitium and collecting duct. 7. The loop of Henle gradually dilutes the isotonic luminal fluid in the course of perinatal differentiation. 8. The thick ascending segment of the loop of Henle differentiates its anisotonic transport by increasing the Na-Chloride transport at constant hydraulic conductivity. 9. Ultrastructure and N-A-K-ATPase activity of the diluting segment (TAL) change greatly during ontogeny. 10. The centrifugal pattern of renal maturation from the juxtamedullary towards the superficial cortical layers leads to an intracortical profile of structure and function.
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PMID:Nephron function and perinatal homeostasis. 15 Feb 48

Papillary component ultrastructure and acid mucopolysaccharide distribution have been investigated in the kidney of the water vole A. terrestris. Structural differences between the descending and ascending parts of the Henle's loop are rather small, cell cytoplasm of these segments being poor in organells. Unusual ultrastructure of the collecting duct epithelium with high level of cytoplasmic organization (elongated thin mitochondria, fairly developed Golgi complex, numerous phagosomes and pinocytotic vesicles, long branching microvilli) was described. Apical membrane of the epithelium is covered by rich glycocalix layer. Heil-positive substrances are located intracellularly inside phagosomes and on vesicle membranes, as well as on the membranes of cisternae of endoplasmic reticulum. Interstitium is abundant, but no close contacts between papillary components were found. Acid mucopolysaccharide content of the interstitium is low, "gel" filter being not formed. The described peculiarities are discussed in relation to water and salt metabolism of the rodents investigated.
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PMID:[Ultrastructural organization of the inner medullary zone of the kidney of the water vole Arvicola terrestris]. 15 94

Histological, histochemical and ultrastructural examinations were performed on renal tissues of rats after prolonged oral administration of the anorectic drug chlorphentermine or of the tricyclic antidepressants iprindole, imipramine and clomipramine. All drugs caused the formation of multilamellated cytoplasmic inclusions throughout the nephron and the collecting duct system, and in interstitial cells. The cytological alterations were most prominent in the glomerular podocytes, in the proximal convoluted tubules, and in the collecting duct system. In view of the histochemical properties (staining with Baker's acid hematein) and the ultrastructural appearance of the cytoplasmic inclusions the cellular alterations are interpreted as a renal manifestation of a generalized lipidosis induced by drugs of amphiphilic character.
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PMID:Lipidosislike renal changes in rats treated with chlorphentermine or with tricyclic antidepressants. 16 10

The effects of ethanol on the water permeability and short-circuit current of the isolated urinary bladder of the toad, Bufo marinus, were investigated. Ethanol alone did not alter the flow of water along an osmotic gradient. The increase in osmotic water flow caused by vasopressin, theophylline or cyclic adenosine-3',5'-monophosphate was inhibited by 4 to 40 mg per ml of ethanol in the mucosal or serosal bathing medium. The inhibition was more marked when ethanol was added to the serosal bathing medium, in spite of the increase in the osmotic gradient across the toad bladder caused by the ethanol. Ethanol had no effect on the increase in sodium transport (short-circuit current) due to vasopressin, although there was a significant inhibition of base-line short-circuit current. It is possible that the water diuresis due to ethanol may result in part from an inhibition of the effect of vasopressin on the collecting duct.
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PMID:Effect of ethanol on the water permeability and short-circuit current of the urinary bladder of the toad and the response to vasopressin, adenosine-3',5'-monophosphate and theophylline. 17 29

An anti-kidney antibody was demonstrated by the indirect immunofluorescence method in the serum of patients with primary tumours of the liver or kidney. The distribution of fluorescence in rabbit kidney was consistent with that of antibody to collecting ducts. The anti-collecting duct antibody (anti-CDA) could be absorbed from serum by normal adult rabbit or human kidney tissue and by one of three specimens of renal-cell carcinoma tissue. Anti-CDA differed from anti-mitochondrial antibodies and from anti-liver/kidney microsomal antibody in the pattern of fluorescent staining obtained with rabbit kidney. Two-hundred sera from patients with cancer and other diseases and forty-three from healthy hospital personnel were tested for anti-CDA. Eleven of the twenty-five positive sera were from patients with primary cancer of the liver or urinary tract, and all but six of the remainder were from patients with tumours involving the liver or with liver disorders that may be associated with nodular hyperplasia or tumour.
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PMID:Circulating antibody to renal collecting ducts in patients with hepatoma or renal-cell carcinoma. 17 72

Vasopressin increases the permeability of the total urinary bladder, an analogue of the mammalian renal collecting duct, to water and small solutes, especially the amide urea. We have observed that three general anesthetic agents of clinical importance, the gases methoxyflurane and halothane and the ultrashortacting barbiturate methohexital, reversibly inhibit vasopressin-stimulated water flow, but do not depress permeability to urea, or the the lipophilic solute diphenylhydantoin. In contrast to their effects in vasopressin-treated bladders, the anesthetics do not inhibit cyclic AMP-stimulated water flow, consistent with an effect on vasopressin-responsive adenylate cyclase. The selectivity of the anesthetic-induced depression of water flow suggests that separate adenylate cyclases and cyclic AMP pools may exist for control of water and urea permeabilities in to toad bladder. Furthermore, theophylline's usual stimulatory effect on water flow, but not its effect on urea permeability, was entirely abolished in methoxyflurane-treated bladders, suggesting that separate phosphodiesterases that control water and urea permeabilities are present as well. We conclude that the majority of water and urea transport takes place via separate pathways across the rate-limiting luminal membrane of the bladder cell, and that separate vasopressin-responsive cellular pools of cyclic AMP appear to control permeability to water and to urea.
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PMID:Selective inhibition of osmotic water flow by general anesthetics to toad urinary bladder. 18 13

Two types of plasma membrane were purified from canine distal renal medulla by the techniques of differential and zonal density-gradient centrifugation followed by free-flow electrophoresis. One group of plasma membranes was identified as basal-laterally derived based on a 30-fold enrichment of Na-K-ATPase, a 20-fold enrichment of vasopressin-stimulated adenylate cyclase, and a 33-fold enrichment of [3H]vasopressin binding sites. The second type of plasma membrane was free of these markers, but had a cholesterol and phospholipid composition similar to them. Alkaline phosphatase also had a similar distribution in the two fractions. This lighter membrane fraction contained a membrane-bound cyclic AMP-dependent protein kinase as well as substrate for this kinase. In addition there was a 26-fold enrichment of specific activity of an anion (SO32-)-activated ATPase which was insensitive to mitochondrial ATPase inhibitor protein, in contrast to the mitochondrial fraction of the tissue. Based on the relative preponderance of collecting duct tissue in the distal medulla and the yield of membrane protein, these membranes are tentatively identified as containing apical membranes of the collecting duct.
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PMID:Purification of distinct plasma membranes from canine renal medulla. 20 99

The mechanism of Ca2+ transport by various segments of the distal nephron was studied in vitro using the isolated perfused tubule technique. Calcium absorption in the distal convoluted tubule (DCT) and the granular portion of the cortical collecting duct (CCTg) was significantly enhanced in the presence of parathyroid hormone (PTH), 3 X 10(-2) U/ml. Na+ was absorbed from and K+ was secreted into the lumen of the DCT. The presence of amiloride (5 X 10(-5) M) or furosemide (5 X 10(-5) M) in the perfusate of DCT each caused a partial inhibition of Na+ but not Ca2+ absorption. The foregoing result with Na+ is consistent with the heterogeneous nature of DCT. Net Na+ absorption and K+ secretion also occurred in the CCTg; both processes were completely inhibited by amiloride. Ca2+ absorption occurred in the thick ascending limb of Henle's loop; it was not enhanced by PTH, and the results were consistent with passive movement. No net Ca2+ movement was observed in the nongranular (light) segment of the cortical collecting tubule in the presence or absence of PTH or dibutyryl cyclic adenosine monophosphate.
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PMID:Calcium transport across segments of the rabbit distal nephron in vitro. 21 62

To understand the role of the kallikrein-kinin system in the kidney all components of the system and their localization need to be considered. About half the kallikrein in urine occurs as the proenzyme which arises in the distal tubule. Kinins are formed in the distal tubule and collecting duct from urokinnogen which is found throughout the tubule. Urine contains about twice as much lysyl-brandykinin as bradykinin. A third kinin, methionyl-lysyl-bradykinin, also can occur in urine. It is probably produced by uropepsin as the kinin is largely formed in acidified urine and its formation is inhibited by pepstatin. The significance of the three kinins is unknown. Kinins are normally slowly (few hours) destroyed in urine. The importance of kallikrein, urokinogen and kininases in regulating the level of kinins needs to be determined.
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PMID:The kallikrein-kinin system in the kidney. 21 52

It is widely accepted that in vivo the function of the papilla of the mammalian kidney is supported primarily by anaerobic metabolism. As a result, the major source of energy for support of function in the papilla is considered to be derived from glycolysis. This orientation originates from two concepts: 1) that in vivo the gaseous environment of the papilla has such a low PO2 that O2 availability limits O2 consumption, and 2) that papillary tissue has a high rate of glycolysis when compared with either cortical tissue or extrarenal tissues. It has also been tacitly assumed that papillary tissue has a "low" O2 uptake. Review of the measurements of PO2 of papillary tissue and of urine PO2 indicates that the PO2 of papillary tissue should not limit its aerobic mitochondrial oxidative metabolism. While the rate of aerobic glycolysis in papillary tissue is high, simultaneously papillary tissue has a rate of O2 uptake similar to that of liver and higher than that of muscle. The major (two-thirds) source of energy for papillary tissue in vitro is from O2 uptake. That papillary tissue is not exclusively dependent on glucose for its energy requirements is indicated by the greater stimulation of papillary tissue QO2 by succinate than by glucose. Thus, papillary tissue has both a high aerobic mitochondrial oxidative metabolism and a high aerobic glycolytic metabolism. It is suggested that the mechanism for the high rate of aerobic glycolysis in the presence of an adequate O2 supply is due to the relatively small mass of mitochondria in papillary tissue in relation to the amount of work done by the tissue. As a result of the limited rate of ATP production by the mitochondrial electron transport chain, the phosphorylation state ([ATP]/[ADP][Pi]) is reduced and the cytoplasmic redox state ([NAD+]/[NADH]) of the papillary collecting duct cells also becomes more reduced; changes in both ratios enhance the rate of glycolysis. This limited metabolic capacity of the collecting duct cells may permit an excess volume of solute and water to be excreted during volume expansion diuresis. The metabolic characteristics of the papilla, when compared to cortex, also provide a basis for the observed differences in substrate selectivity of cortex and medulla with respect to utilization of glucose and lactate. The experimental approaches that may provide information bearing on the suggested mechanisms for regulation of papillary metabolism in relation to tubular work functions are indicated.
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PMID:Is the function of the renal papilla coupled exclusively to an anaerobic pattern of metabolism? 22 Aug 81


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