The effects of glutathione and adenosine on plasma membrane ATPases of the corneal endothelium. An hypothesis on the stimulatory mechanism of perfused glutathione upon deturgescence

Reduced glutathione (0.3 mM) stimulates the activity of sodium-potassium activated ATPase (Na+ K+ ATPase) by 54% in plasma membranes prepared from bovine corneal endothelial cells. Oxidized glutathione, however, has no effect on Na+ K+ AT Pase activity in the same tissue, although it does inhibit magnesium activated ATPase (Mg ATPase) by approximately 30%. Adenosine neither stimulates nor inhibits either Na+ K+ ATPase or Mg++ ATPase in these plasma membranes. It is postulated that the stimulatory effect of glutathione on deturgescence stems from the direct reaction of the reduced form of the tripeptide on sulfhydryl groups located on plasma membranes of corneal endothelial cells. It is highly probable that these sulfhydryl groups are part of the Na+ K+ ATPase complex itself.