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Pflügers Archiv

, Volume 419, Issue 6, pp 583–587 | Cite as

Zinc uptake by proximal cells isolated from rabbit kidney: Effects of cysteine and histidine

  • Bertrand Gachot
  • Michel Tauc
  • Luc Morat
  • Philippe Poujeol
Transport Processes, Metabolism and Endocrinology; Kidney, Gastrointestinal Tract, and Exocrine Glands

Abstract

The aim of this study was to characterize the mechanisms of zinc transport in proximal cells isolated from rabbit kidney cortex. Uptakes of 65Zn were assessed under initial rate conditions, after 0.5 min of incubation. The kinetic parameters obtained at 20°C were a Km of 15.0±1.5 μM, a Jmax of 208.0±8.4 pmol min−1 (mg protein)−1, and an unsaturable constant of 0.259±0.104 (n=8). Cadmium competitively inhibited the zinc uptake, with a Ki value of 13.0±2.8 μM, while zinc competitively inhibited 109Cd uptake by isolated cells. Cysteine and histidine stimulated zinc transport at an amino acid∶zinc molar ratio ranging from 1∶1 to 8∶1. This stimulation was not observed in the absence of a sodium gradient. At a molar ratio greater than 16∶1 (i.e., 400 μM cysteine or histidine and 25 μM Zn), there was evidence of inhibition. These data suggest that zinc enters renal proximal cells (a) as a free ion via a saturable carrier-mediated process or an unsaturable pathway and (b) complexed with cysteine or histidine, by means of a sodium/amino acid cotransport mechanism.

Key words

Isolated proximal cells Kidney Zinc Cysteine Histidine 

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References

  1. 1.
    Abu-Hamdan DK, Migdal SD, Whitehouse R, Rabbani P, Prasad AS, McDonald FD (1981) Renal handling of zinc: effect of cysteine infusion. Am J Physiol 241:F487-F494Google Scholar
  2. 2.
    Askari A, Long CL, Blakemore WS (1982) Net metabolic changes of zinc, copper, nitrogen, and potassium balances in skeletal trauma patients. Metabolism 31:1185–1193Google Scholar
  3. 3.
    Cousins RJ (1985) Absorption, transport and hepatic metabolism of copper and zinc: special reference to metallothionein and ceruloplasmin. Physiol Rev 65:239–309Google Scholar
  4. 4.
    Foulkes EC (1985) Interaction between metals in rat jejunum: implications on the nature of cadmium uptake. Toxicology 37:117–125Google Scholar
  5. 5.
    Giroux EL, Henkin RI (1972) Competition for zinc among serum albumin and amino acids. Biochim Biophys Acta 273:64–72Google Scholar
  6. 6.
    Hambidge KM (1977) The role of zinc and other trace metals in pediatric nutrition and health. Pediatr Clin North Am 24:95–106Google Scholar
  7. 7.
    Meret S, Henkin RI (1971) Simultaneous direct estimation by atomic absorption spectrophotometry of copper and zinc in serum, urine and cerebrospinal fluid. Clin Chem 17:369–373Google Scholar
  8. 8.
    Neame KD, Richard TG (1972) Elementary kinetics of membrane carrier transport. Blackwell, Oxford, pp 56–79Google Scholar
  9. 9.
    Poujeol P, Vandewalle A (1985) Phosphate uptake by proximal renal cells isolated from rabbit kidney. Am J Physiol 249:F74-F83Google Scholar
  10. 10.
    Prasad AS (1979) Clinical, biochemical and pharmacological role of zinc. Annu Rev Pharmacol Toxicol 20:393–426Google Scholar
  11. 11.
    Raffaniello RD, Wapnir RA (1989) Zinc uptake by isolated rat enterocytes: effect of low molecular weight ligands. Proc Soc Exp Biol Med 192:219–224Google Scholar
  12. 12.
    Silbernagl S (1988) The renal handling of amino acids and peptides. Physiol Rev 68:911–1007Google Scholar
  13. 13.
    Steele TH (1973) Dissociation of zinc excretion from other cations in man. J Lab Med 81:507–514Google Scholar
  14. 14.
    Tacnet F, Watkins DW, Ripoche P (1990) Studies of zinc transport into brush-border membrane vesicles isolated from pig small intestine. Biochim Biophys Acta 1024:323–330Google Scholar
  15. 15.
    Templeton DM (1990) Cadmium uptake by cells of renal origin. J Biol Chem 265:21 764–21 770Google Scholar
  16. 16.
    Wapnir RA, Stiel L (1986) Zinc intestinal absorption in rats: specificity of amino acids as ligands. J Nutr 116:2171–2179Google Scholar
  17. 17.
    Yunice AA, King RW Jr, Kraikitpanitch S, Haygood CC, Lindeman RD (1978) Urinary zinc excretion following infusions of zinc sulfate, cysteine, histidine or glycine. Am J Physiol 235:F40-F45Google Scholar
  18. 18.
    Zlotkin SH (1989) Nutrient interactions with total parenteral nutrition: effect of histidine and cysteine intake on urinary zinc excretion. J Pediatr 114:859–864Google Scholar

Copyright information

© Springer-Verlag 1991

Authors and Affiliations

  • Bertrand Gachot
    • 1
  • Michel Tauc
    • 1
  • Luc Morat
    • 1
  • Philippe Poujeol
    • 1
  1. 1.Département de Biologie cellulaire et moléculaire, Service de biologie cellulaireCEN SaclayGif sur Yvette, CedexFrance

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