Reduced glutathione release into rat plasma by extrahepatic
tissues.
Burk, Raymond F., and Kristina E. Hill.
Division of Gastroenterology, Department of Medicine and Center in
Molecular Toxicology, Vanderbilt University School of Medicine,
Nashville, Tennessee 37232
APStracts 2:0081G, 1995.
The liver is the only tissue that has been demonstrated directly to
secrete GSH into the plasma. The present experiments were carried out
to determine whether extrahepatic tissues secrete GSH as well.
Phorone, a compound which depletes glutathione through glutathione S
-transferase dependent conjugation with GSH, was administered to
fasted rats in a dose of 250 mg/kg. Two hours later, glutathione
concentrations were reduced to: liver 2%, plasma 17%, skeletal muscle
63%. This showed that plasma and muscle glutathione were not depleted
to the same extent as liver glutathione. Glutathione concentration in
plasma from the hepatic vein was not higher than concentrations in
plasma from the portal vein and from the aorta, indicating that the
depleted liver was not releasing glutathione into the plasma. Total
glutathione and GSH were higher in plasma from the femoral vein than
in plasma from the aorta under these same conditions. This indicates
that the leg releases GSH under conditions of absent hepatic GSH
release when plasma glutathione concentrations are decreased. These
results suggest that muscle secretes GSH into the extracellular space
and raise the possibility that other tissues secrete GSH as well.
Further studies will be required to determine whether GSH release by
extrahepatic tissues is affected by the plasma glutathione
concentration.
Received 28 December 1994; accepted in final form 20 April 1995.
APS Manuscript Number G507-4.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 2 May 1995.