Effect of ethanol on Na+-Pi uptake in opossum kidney cells: Role of membrane fluidization and reactive oxygen species.
- Author:
In Ho PARK
1
;
Moon Young HWANG
;
Jae Suk WOO
;
Jin Sup JUNG
;
Yong Keun KIM
Author Information
1. )Department of Physiology, College of Medicine, Pusan National University, Pusan, 602-739 South Korea.
- Publication Type:Original Article
- Keywords:
Alcohol;
Na-Pi;
uptake;
Antioxidants;
Radical scavengers;
Renal epithelial
- MeSH:
Alanine;
Alcohol Dehydrogenase;
Amino Acids;
Antioxidants;
Catalase;
Cell Death;
Cell Line;
Chelating Agents;
Ethanol*;
Glucose;
Glycine;
Hydroxyl Radical;
Iron;
Kidney*;
Membranes*;
Opossums*;
Reactive Oxygen Species*;
Superoxide Dismutase
- From:The Korean Journal of Physiology and Pharmacology
1999;3(5):529-538
- CountryRepublic of Korea
- Language:English
-
Abstract:
This study was undertaken to examine the effect of ethanol on Na+-dependent phosphate (Na+-Pi) uptake in opossum kidney (OK) cells, an established renal proximal tubular cell line. Ethanol inhibited Na+-dependent component of phosphate uptake in a dose-dependent manner with I50 of 8.4%, but it did not affect Na+-independent component. Similarly, ethanol inhibited Na+-dependent uptakes of glucose and amino acids (AIB, glycine, alanine, and leucine). Microsomal Na+-K+-ATPase activity was not significantly altered when cells were treated with 8% ethanol. Kinetic analysis showed that ethanol increased Km without a change in Vmax of Na+-Pi uptake. Inhibitory effect of n-alcohols on Na+-Pi uptake was dependent on the length of the hydrocarbon chain, and it resulted from the binding of one molecule of alcohol, as indicated by the Hill coefficient (n) of 0.8-1.04. Catalase significantly prevented the inhibition, but superoxide dismutase and hydroxyl radical scavengers did not alter the ethanol effect. A potent antioxidant DPPD and iron chelators did not prevent the inhibition. Pyrazole, an inhibitor of alcohol dehydrogenase, did not attenuate ethanol-induced inhibition of Na+-Pi uptake, but it prevented ethanol-induced cell death. These results suggest that ethanol may inhibit Na+-Pi uptake through a direct action on the carrier protein, although the transport system is affected by alterations in the lipid environment of the membrane.
