Enteral glutamate is the preferential source for mucosal
glutathione synthesis in fed piglets.
Reeds, Peter J., Douglas G. Burrin, Barbara Stoll, Farook Jahoor,
Linda Wykes Joseph Henry & Margaret E. Frazer.
USDA/ARS Children's Nutrition Research Center, Department of
Pediatrics, Baylor College of Medicine, 1100, Bates Street, Houston,
TX 77030
APStracts 4:0089E, 1997.
To measure the source and rate of mucosal glutathione (GSH) synthesis,
fed piglets (28 d old; 7.7 kg) received a 6 h infusion of
intragastric [U-13C]glutamate (N=11) either with (N=5) or without
(N=6) an intragastric infusion of [1-13C]glycine (0 to 6 h) and [1,2
-13C2(U-13C)]glycine (3 to 6 h). 84% of the labeled mucosal GSH
-glutamate and 86% of the luminal GSH-glutamate was [13C5]. The
tracer:tracee ratio of GSH-[U-13C]glutamate was 75% of that of
mucosal glutamate. 60% of the labeled mucosal glutamate was [13C1],
[13C2] or [13C3] but the tracer:tracee ratios of these isotopomers in
GSH-glutamate were not significantly different from zero. After 3 of
infusion, the tracer:tracee ratio of GSH-[U-13C]-glycine was 46%, and
after 6 h of infusion GSH-[13C1]-glycine was 82% of that of mucosal
glycine. This suggests that the half life of mucosal GSH was 2.7 +/-
0.1 h. We conclude that, in fed piglets, mucosal GSH-glutamate had
derived largely from the direct metabolism of enteral glutamate
rather than from glutamate that had been metabolized within the
mucosa.
Received 3 February 1997; accepted in final form 7 April 1997.
APS Manuscript Number E49-7.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 13 May 1997