[Ultrastructural-cytochemical features of the plasma membrane of sodium-transporting cells].
Electron microscopic and biochemical studies of the ATP-ase activity in different regions of the nephron and in the kidney microsomal fraction of the rat have revealed a pronounced increase of the total and Na+-+K+-ATP-ase activity in the process of compensatory hypertrophy. A decrease of the enzymatic activity was noted predominantly in proximal tubules under loading the animals by isotonic NaCl solution and after adrenalectomy--mainly in distal tubules. This speaks of the inhibition of the sodium-reabsorbing system in them. The transport of isotonic fluid in collecting tubes is accompanied by widening intercellular lacunae together with an increase of the ATP-ase activity of the lateral plasmic membrane of neighbouring cells. The data obtained suggest a close correlation between the electron-microscopically revealed ATP-ase activity of the plasmic membrane of tubular cells and the functional activity of the sodium-transporting system. A morphological equivalent of the sodium pump is a plasmolemma--mitochondrial pump which is characterized by: a) well developed foldness of the basal plasmic membrane where the enzymatic system is disposed; b) the high total and Na++K+-ATP-ase activity cytochemically and biochemically revealed; c) numerous regularly disposed mitochondria, having close contacts with the folds of the basal plasmic membrane.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000315:Adrenalectomy; D000818:Animals; D001693:Biological Transport, Active; D002462:Cell Membrane / Q000201:enzymology*; D006651:Histocytochemistry; D007668:Kidney / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure*; D007684:Kidney Tubules / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure; D008854:Microscopy, Electron; D008861:Microsomes / Q000201:enzymology*; D008928:Mitochondria / Q000201:enzymology; D009392:Nephrectomy; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D013997:Time Factors
D012964:Sodium; D000251:Adenosine Triphosphatases
Ul'trastrukturno-tsitokhimicheskie osogennosti plazmaticheskoĭ membrany natriĭtransportiruiushchikh kletok