ISSN:
1432-1424
Keywords:
AT-125
;
gamma-glutamyl transpeptidase
;
renal brushborder membrane
;
amino acids transport
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary 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-[αS, 5S]-α-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°C with rat brushborder membrane vesicles. AT-125 given to ratsin 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 bothin vivo andin 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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01868772
Permalink
