Glutathione transport and glutathione-dependent detoxication in
small intestine of rats exposed in vivo to hypoxia.
Bai, Changli, and Dean P. Jones.
Department of Biochemistry, Emory University School of Medicine,
Atlanta, GA 30322
APStracts 3:0136G, 1996.
The effects of hypoxia on glutathione (GSH) concentration and GSH
-related enzyme and transport systems were studied in the small
intestine of rats exposed to 8-10 days of 10.5% O2. Exposure to
hypoxia resulted in a 40% lower GSH concentration in enterocytes and
a 50% lower concentration in blood plasma. Activities of GSH-related
detoxication enzymes in the intestinal epithelium were largely
unaffected by hypoxic exposure. GSH degradation and synthesis rates
in enterocytes isolated from hypoxic rats were comparable to rates in
normoxic controls, but GSH uptake rate was decreased by 30%.
Stimulation of absorption of GSH by phenylephrine, such as occurs in
control rats, was not detectable in isolated, vascularly perfused
intestines of hypoxic rats. Decreased GSH uptake was associated with
enhanced transepithelial appearance of thiobarbituric acid-reactive
substances in everted intestinal sacs incubated with peroxidized
methyl linoleate. These results suggest that chronic hypoxia results
in impaired uptake of GSH in the small intestine and this may result
in impaired GSH-related defense mechanisms in the small intestine.
Received 2 February 1994; accepted in final form 21 June 1996.
APS Manuscript Number G46-4.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 25 July 1996