Effects of fasting and glutathione depletors on the GSH-dependent enzyme system in the gastrointestinal mucosa of the rat.
In rats, the glutathione content of the gastrointestinal mucosa amounted to 50-60% of that of the liver. The GSH-S-transferase activity towards an aryl substrate (CDNB) was low in the stomach, colon and rectum, i.e. 5% of hepatic activity. In the small intestine there was a typical decline of activity from proximal to distal segments. GSH-Peroxidase was much lower in the intestinal mucosa as compared to the stomach and liver, whereas the GSSG-reductase was 2-3 times higher in the gastrointestinal tract in comparison to the liver. Fasting for 24 h significantly decreased the GSH content, GSH-aryltransferase and GSSG-reductase activities in the liver but not in the intestine, where even higher GSH concentrations were found in the proximal segments. L-Buthionine-sulfoximine, an inhibitor of the GSH-synthesis, caused a marked decrease of the GSH levels in the liver, stomach, proximal small intestine, colon and rectum and a concomitant decline in GSSG-reductase activity. Among the GSH-depleting agents, paracetamol exerted the strongest effect, whereas 1,1-dichloroethylene and phorone only decreased the GSH content in the liver and stomach.
Siegers
C P
CP
Institute of Toxicology, Medical University of Lübeck, FRG.
Bartels
L
L
Riemann
D
D
D000818:Animals; D019328:Buthionine Sulfoximine; D005215:Fasting; D005753:Gastric Mucosa / Q000201:enzymology*; D005978:Glutathione / Q000378:metabolism / Q000502:physiology*; D005979:Glutathione Peroxidase / Q000037:antagonists & inhibitors / Q000378:metabolism; D005981:Glutathione Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D005982:Glutathione Transferase / Q000037:antagonists & inhibitors / Q000378:metabolism; D007413:Intestinal Mucosa / Q000201:enzymology*; D008297:Male; D008717:Methionine Sulfoximine / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D008717:Methionine Sulfoximine; D019328:Buthionine Sulfoximine; D005979:Glutathione Peroxidase; D005982:Glutathione Transferase; D005981:Glutathione Synthase; D005978:Glutathione