The long-term goals of this proposal are to elucidate the failure of hepatocyte volume regulation during chronic ethanol ingestion, which results in hepatomegaly. Liver enlargement in turn leads to portal hypertension, impaired microcirculation, and anoxic degeneration of hepatic function. The immediate goal is to determine whether chronic ethanol ingestion in mice or acute administration of ethanol to hepatocytes in primary culture diminishes the capability of liver cells to regulate their volume. The project will utilize a novel, electrophysiological technique to measure change in hepatocyte water volume.
The specific aims are 1) to determine the membrane water permeability coefficient for hepatocytes in primary culture and whether it is affected by ethanol; 2) to determine whether hepatocytes in primary monolayer culture regulate their volume in response to perturbations in external osmolality and whether volume regulation diminishes with chronic and acute effects of ethanol; 3) to determine whether rapid volume regulation in cultured hepatocytes facilitates secondary active transport of L-alanine by compensating for the osmolality of accumulated organic solute and whether this diminishes due to ethanol; 4) to determine whether passive, redistribution of cellular Cl- is voltage-driven by osmotically-induced changes in cell transmembrane potential, which constitutes a novel means for control of cell volume. Successful completion of this project will expand our knowledge of the mechanisms of hepatocyte volume regulation. Moreover, the health-relatedness of these studies will be the generation of new information on how chronic and acute effects of ethanol inhibit hepatocyte volume regulation, which in turn results in cell hypertrophy, hepatomegaly, and the sequelae of deteriorated hepatic function.

Agency
National Institute of Health (NIH)
Institute
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
Type
Research Project (R01)
Project #
5R01AA008867-02
Application #
2044893
Study Section
Biochemistry, Physiology and Medicine Subcommittee (ALCB)
Project Start
1991-06-01
Project End
1994-05-31
Budget Start
1992-06-01
Budget End
1993-05-31
Support Year
2
Fiscal Year
1992
Total Cost
Indirect Cost
Name
East Tennessee State University
Department
Physiology
Type
Schools of Medicine
DUNS #
City
Johnson City
State
TN
Country
United States
Zip Code
37614
Veech, R L; Gates, D N; Crutchfield, C et al. (1994) Metabolic hyperpolarization of liver by ethanol: the importance of Mg2+ and H+ in determining impermeant intracellular anionic charge and energy of metabolic reactions. Alcohol Clin Exp Res 18:1040-56
Wondergem, R; Davis, J (1994) Ethanol increases hepatocyte water volume. Alcohol Clin Exp Res 18:1230-6
Wang, K; Wondergem, R (1993) Hepatocyte water volume and potassium activity during hypotonic stress. J Membr Biol 135:137-44
Miao, K; Wondergem, R; Hossler, F E et al. (1993) Contributions of K+, Na+, and Cl- to the membrane potential of intact hamster vascular endothelial cells. J Cell Physiol 156:550-9
Wang, K; Wondergem, R (1993) Redistribution of hepatocyte chloride during L-alanine uptake. J Membr Biol 135:237-44
Wang, K; Wondergem, R (1992) Mouse hepatocyte membrane potential and chloride activity during osmotic stress. Am J Physiol 263:G566-72
Wang, K N; Wondergem, R (1991) Effects of hyperosmotic medium on hepatocyte volume, transmembrane potential and intracellular K+ activity. Biochim Biophys Acta 1069:187-96