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Transport interactions of cystine and dibasic amino acids in isolated rat renal tubules.

Publication ,  Journal Article
Foreman, JW; Hwang, SM; Segal, S
Published in: Metabolism
January 1980

Isolated renal cortical tubules prepared from adult male Sprague-Dawley rats were used to study the nature of cystine entry into tubule cells and its transport interactions with dibastic amino acids. The uptake of cystine over time was progressive, reaching a steady-state after 60 min of incubation. Analysis of the intracellular pool after incubation revealed that a significant fraction of the transported cystine was reduced to cysteine. A kinetic analysis of uptake demonstrated that two systems for cellular entry of cystine existed with a Km1 of 0.012 mM and Km2 of 0.55 mM. Cystine uptake was sodium dependent with an apparent Km for sodium of 36 mEq/liter. Lysine inhibited cystine uptake via the low Km system, but appeared not to inhibit cystine uptake via the high Km system. Ornithine, leucine, and isoleucine each inhibited cystine uptake via the low Km system. Arginine appeared to affect both systems for cystine uptake. Cystine inhibited the uptake of lysine by isolated renal tubules. The data suggest that cystine at physiologic concentrations is transported into renal tubule cells nearly equally by two systems, of which, the low Km system is shared with the dibasic amino acids. A defective low Km system could in part explain human cystinuria.

Duke Scholars

Published In

Metabolism

DOI

ISSN

0026-0495

Publication Date

January 1980

Volume

29

Issue

1

Start / End Page

53 / 61

Location

United States

Related Subject Headings

  • Sodium
  • Rats
  • Ornithine
  • Male
  • Lysine
  • Leucine
  • Kinetics
  • Kidney Tubules
  • Isoleucine
  • Endocrinology & Metabolism
 

Citation

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Foreman, J. W., Hwang, S. M., & Segal, S. (1980). Transport interactions of cystine and dibasic amino acids in isolated rat renal tubules. Metabolism, 29(1), 53–61. https://doi.org/10.1016/0026-0495(80)90098-0
Foreman, J. W., S. M. Hwang, and S. Segal. “Transport interactions of cystine and dibasic amino acids in isolated rat renal tubules.Metabolism 29, no. 1 (January 1980): 53–61. https://doi.org/10.1016/0026-0495(80)90098-0.
Foreman JW, Hwang SM, Segal S. Transport interactions of cystine and dibasic amino acids in isolated rat renal tubules. Metabolism. 1980 Jan;29(1):53–61.
Foreman, J. W., et al. “Transport interactions of cystine and dibasic amino acids in isolated rat renal tubules.Metabolism, vol. 29, no. 1, Jan. 1980, pp. 53–61. Pubmed, doi:10.1016/0026-0495(80)90098-0.
Foreman JW, Hwang SM, Segal S. Transport interactions of cystine and dibasic amino acids in isolated rat renal tubules. Metabolism. 1980 Jan;29(1):53–61.
Journal cover image

Published In

Metabolism

DOI

ISSN

0026-0495

Publication Date

January 1980

Volume

29

Issue

1

Start / End Page

53 / 61

Location

United States

Related Subject Headings

  • Sodium
  • Rats
  • Ornithine
  • Male
  • Lysine
  • Leucine
  • Kinetics
  • Kidney Tubules
  • Isoleucine
  • Endocrinology & Metabolism