Absence of a role of gamma-glutamyl transpeptidase in the transport of amino acids by rat renal brushborder membrane vesicles.

Published

Journal Article

The role of the enzyme, gamma-glutamyl transpeptidase on the uptake of amino acids by the brushborder membrane of the rat proximal tubule was examined by inhibiting it with AT-125 (L-[alpha S, 5S]-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid). AT-125 inhibited 98% of the activity of gamma-glutamyl transpeptidase when incubated for 20 min at 37 degrees C with rat brushborder membrane vesicles. AT-125 given to rats in vivo inhibited 90% of the activity of gamma-glutamyl transpeptidase in subsequently isolated brushborder membrane vesicles from these animals. AT-125 inhibition of gamma-glutamyl transpeptidase both in vivo and in vitro had no effect on the brushborder membrane uptake of cystine. Similarly, there was no effect of gamma-glutamyl transpeptidase inhibition by AT-125 on glutamine, proline, glycine, methionine, leucine or lysine uptake by brushborder membrane vesicles. Furthermore, the uptake of cystine by isolated rat renal cortical tubule fragments, in which the complete gamma-glutamyl cycle is present, was unaffected by AT-125 inhibition of gamma-glutamyl transpeptidase. Therefore, in the two model systems studied, gamma-glutamyl transpeptidase did not appear to play a role in the transport of amino acids by the renal brushborder membrane.

Full Text

Duke Authors

Cited Authors

  • Hsu, BY; Foreman, JW; Corcoran, SM; Ginkinger, K; Segal, S

Published Date

  • January 1, 1984

Published In

Volume / Issue

  • 80 / 2

Start / End Page

  • 167 - 173

PubMed ID

  • 6148423

Pubmed Central ID

  • 6148423

Electronic International Standard Serial Number (EISSN)

  • 1432-1424

International Standard Serial Number (ISSN)

  • 0022-2631

Digital Object Identifier (DOI)

  • 10.1007/bf01868772

Language

  • eng