Transportvorgänge und Stoffwechselprozesse in isolierten Sammelrohrzellen der Nierenpapille

摘要: Taking into account recent results obtained with isolated papillary collecting duct cells the metabolic pathways and membrane transport systems of are reviewed. The plasma membranes contain a luminal proton AT-Pase contraluminal Cl−/HCO 3 − exchanger which involved in secretion; sodium channel Na+/K+-AT-Pase for reabsorption; K+ potassium secretion, Na+/K+/Cl− cotransport system chloride and/or volume regulation. also possess organic substrates osmolytes. D-glucose, main substrate is taken up cell by sodium-independent D-glucose aK m 1.2 mM. contains mechanisms mediate sorbitol release medium. This mechanism stimulated when exposed to media low osmolality inhibited high osmolality. used as anaerobic aerobic glycolysis precursor synthesis via aldose reductase, highly enriched cells. show gluconeogenic activity evidenced incorporation labeled carbon from L-alanine glycerol, sorbitol, myo-inositol. Accordingly, fructose-1,6-biphosphatase activity. Sorbitol contrast permeability not affected osmolarity. These studies indicate that transmembrane intracellular metabolism strongly depend on composition interstitium plasticity allows cope successfully osmotic challenges connected urine concentration or dilution.