Summary
Stationary microperfusion of the rat proximal convoluted tubule together with simultaneous perfusion of the peritubular blood capillaries has been used to studyl-histidine andl-glutamine transport in the rat kidney. When histidine and glutamine concentrations in the capillary perfusate were 14.1 and 6.9 mmol/kg respectively, the luminal concentrations stabilized at about 5.6 and 2.0 mmol/kg respectively. The transepithelial concentration differences at steady-state were 8 mmol/kg (histidine) and 5 mmol/kg (glutamine). The results indicated that when peritubular capillary concentrations were high enough, nett passive back-flux of amino acids down a concentration gradient can become of considerable importance in determining nett reabsorptive rates.
When the steady-state epithelial concentration differences were analysed in relation to perfusion site within the proximal convolution, it was found that the gradient was greatest near the glomerulus and smallest near thepars recta, the rate of decline along the convolution being approximately linear. This inhomogeneity of the proximal tubule seems to be due to a diminution in nett amino acid transport by about 50%. The results correlate well with the observation in Fanconi syndrome (congenital renal aminoaciduria with rickets) that only the first 1/3 of the proximal tubule usually shows marked pathological changes.
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Baldamus, C. A., Hierholzer, K., Rumrich, G. Stolte, H., Uhlich, E., Ullrich., K. J., Wiederholt, M.: Natriumtransport in den proximalen, Tubuli und den Sammelrohren bei Variation der Natriumkonzentration im umgebenden Interstitium. Pflügers Arch.310, 354–368 (1969).
Burg, M. B., Orloff, J.: Control of fluid absorption in the renal proximal tubule. J. clin. Invest.47, 2016–2024 (1968).
Chan, Y.-L., Huang, K. C.: Renal excretion ofd-tryptophan, 5-hydroxytryptamine, and 5-hydroxyindoleacetic acid in rats. Amer. J. Physiol.224, 140–143 (1973).
Cushny, A. R.: The Secretion of the Urine, p. 17 footnote, 1 st ed. London: Longmans, Green & Co. 1917.
Darmady, E. M., Stranack, F.: Microdissection of the nephron in disease. Brit. med. Bull.13, 21–25 (1957).
Frömter, E., Müller, C. W., Knauf, H.: Fixe negative Wandladungen im proximalen Konvolut der Rattenniere und ihre Beeinflussung durch Calciumionen. In: Aktuelle Probleme des Elektrolyt- und Wasserhaushaltes, Nierenbiopsie, p. 61. B. Watschinger, ed Vienna: Wien. Med. Akad. 1969.
Frömter, E., Müller, C. W., Wick, T.: Permeability properties of the proximal tubular epithelium in the rat kidney studied with electrophysiological methods. In: Electrophysiology of epithelial cells, pp. 119–146. G. Giebisch, ed. Stuttgart: Schattauer 1971.
Greenstein, J. P., Winitz, M.: Chemistry of the amino acids, vol. 1, p. 487. New York: Wiley 1961.
Györy, A. Z., Lingard, J. M., Young, J. A.: Kinetics of Na+ reabsorption in rat proximal tubules perfusedin vivo. Proc. Aust. Physiol. Pharmacol. Soc. 4, (in press) (1973).
Lingard, J., Rumrich, G., Young, J. A.: A demonstration that the proximal convolution of the rat nephron is not homogeneous with respect to amino acid reabsorption using stationary microperfusion techniques. Proc. Aust. Physiol. Pharmacol. Soc.3, No. 1, 57–58 (1972),
Lingard, J., Rumrich, G., Young, J. A.: Kinetics ofl-histidine transport in the proximal convolution of the rat nephron studied using the stationary microperfusion technique. Pflügers Arch.342, 13–28 (1973).
Owen, E. E., Robinson, R. R.: Amino acid extraction and ammonia metabolism by the human kidney during the prolonged administration of ammonium chloride. J. clin. Invest.42, 263–276 (1963).
Rytand, D. A.: The number and size of mammalian glomeruli as related to kidney and to body weight, with methods for their enumeration and measurement. Amer. J. Anat.62, 507–519 (1938).
Shalhoub, R., Webber, W., Glabman, S., Canessa-Fischer, M., Klein, J., de Haas, J., Pitts, R. F.: Extraction of amino acids from and their addition to renal blood plasma. Amer. J. Physiol.204, 181–186 (1963).
Tuck, R. R., Setchell, B. P., Waites, G. M. H., Young, J. A.: The composition of the fluid collected by micropuncture and catheterization from the seminiferous tubules and rete testis of rats. Pflügers Arch.318, 225–243 (1970).
Tune, B. M., Burg, M. B.: Glucose transport by proximal renal tubules. Amer. J. Physiol.221, 580–585 (1971).
Tune, B. M., Burg, M. B., Patlak, C. S.: Characteristics ofp-aminohippurate transport in proximal renal tubules. Amer. J. Physiol.217, 1057–1063 (1969).
Ullrich, K. J., Frömter, E., Baumann, K.: Micropuncture and microanalysis in kidney physiology. In: Laboratory techniques in membrane biophysics, pp. 106–129. H. Passow and R. Stämpfli, eds. Berlin-Göttingen-Heidelberg: Springer 1969.
Ullrich, K. J., Radtke, H. W., Rumrich, G.: The role of bicarbonate and other buffers on isotonic fluid absorption in the proximal convolution of the rat kidney. Pflügers Arch.330, 149–161 (1971).
Ullrich, K. J., Sauer, F., Frömter, E.: Transport parameters for sodium, chloride and bicarbonate in the proximal tubules of the rat kidney. In: Recent advances in renal physiology, pp. 2–13. H. Wirz and F. Spinelli, eds. Basel: Karger 1972.
Wright, L. A., Nicholson, T. F.: The proximal tubular handling of amino acids and other ninhydrin-positive substances. Canad. J. Physiol.44, 183–193 (1966).
Young, J. A., Edwards, K. D. G.: Clearance and stop-flow studies on histidine and methyldopa transport by rat kidney. Amer. J. Physiol.210, 667–675 (1966).
Young, J. A., Freedman, B. S.: Renal tubular transport of amino acids. Clin. Chem.17, 245–266 (1971).
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Lingard, J., Rumrich, G. & Young, J.A. Reabsorption ofl-glutamine andl-histidine from various regions of the rat proximal convolution studied by stationary microperfusion: Evidence that the proximal convolution is not homogeneous. Pflugers Arch. 342, 1–12 (1973). https://doi.org/10.1007/BF00593246
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DOI: https://doi.org/10.1007/BF00593246