HEPATIC EXPORT OF GLUTATHIONE AND UPTAKE OF CONSTITUENT AMINO-ACIDS, GLUTAMATE AND CYSTEINE, IN BROILERS IN-VIVO

Citation
S. Wang et al., HEPATIC EXPORT OF GLUTATHIONE AND UPTAKE OF CONSTITUENT AMINO-ACIDS, GLUTAMATE AND CYSTEINE, IN BROILERS IN-VIVO, Poultry science, 77(10), 1998, pp. 1556-1564
Citations number
50
Categorie Soggetti
Agriculture Dairy & AnumalScience
Journal title
ISSN journal
00325791
Volume
77
Issue
10
Year of publication
1998
Pages
1556 - 1564
Database
ISI
SICI code
0032-5791(1998)77:10<1556:HEOGAU>2.0.ZU;2-O
Abstract
This study was conducted to document the glutathione (GSH) cycle (inte rorgan circulation of GSH) in broilers in vivo. Two experiments were c onducted on 36 anesthetized male, broilers (n = 6 per treatment) impla nted with cannulae in. the carotid artery, hepatic portal, and hepatic veins. Plasma GSH, glutamate, cysteine, cystine and cysteinylglycine levels in each vessel were monitored following a bolus injection [Expe riment (Exp.) 1] or 30 min continuous infusion (Exp. 2) of GSH, or a g amma-glutamyltranspeptidase inhibitor (AT125) into the hepatic portal vein. Controls received saline alone. The GSH and AT125 treatments wer e used to determine the effect of increasing the prehepatic GSH bad an d of inhibiting systemic GSH degradation, respectively, on the GSH cyc le. Hepatic export of GSH was clearly evident in all three treatment g roups in both experiments (Exp.). The GSH and AT125 treatments raised amino acid levels in some or all of the vessels, whereas cysteinylglyc ine was elevated by AT125 and depressed by the GSH treatment compared to Controls. Hepatic uptake of glutamate, cysteine, and/or cystine was observed in Controls and GSH-treated birds, but not in birds given AT 125 (Exp. 2). Neither hepatic export nor uptake of cysteinylglycine wa s observed in any treatment group. The results clearly demonstrate the ability of the avian Liver to export GSH into the general circulation despite alterations that might arise from changes in extra-hepatic ab ility to utilize GSH or its constituent amino acids.