Na,K-ATPase of cultured bovine lens epithelial cells: H2O2 effects.
Na,K-ATPase function was studied in cultured bovine lens epithelial cells under confluent and non-confluent conditions. The affinity of the Na,K-ATPase for the cardiac glycoside, ouabain, differs between the confluent and non-confluent cultures. The confluent cells have a higher affinity for ouabain than do the non-confluent cells. The ouabain affinity of the confluent cells is similar to that for the Na,K-ATPase isolated from the bovine axolemma and the bovine lens cortex. The ouabain affinity of the non-confluent cells is similar to that for the Na,K-ATPase of the renal medulla and bovine lens epithelium. Similar results are not found with confluent and non-confluent MDCK cells. H2O2 treatment of confluent and non-confluent lens epithelial cell cultures has differing effects on the Na,K-ATPase function. In the confluent cell preparations, H2O2 affects K(+)-dependent dephosphorylation of the intermediate phosphoenzyme. In the non-confluent preparations. H2O2 appears to inhibit K(+)-occlusion.
Garner
M H
MH
Department of Ophthalmology, University of California, Irvine 92715.
Bahador
A
A
Thi Nguyen
B T
BT
Wang
R R
RR
Spector
A
A
D000818:Animals; D002417:Cattle; D002460:Cell Line; D002478:Cells, Cultured; D004285:Dogs; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects / Q000201:enzymology; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007908:Lens, Crystalline / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D010042:Ouabain / Q000494:pharmacology; D010766:Phosphorylation; D011188:Potassium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism*
D010042:Ouabain; D006861:Hydrogen Peroxide; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium