Effects of chronic ethanol ingestion on the activity of rat liver mitochondrial 2',3'-cyclic nucleotide 3'-phosphohydrolase.
Chronic ethanol ingestion induced a 47% increase in the specific activity of 2',3'-cyclic nucleotide 3'-phosphohydrolase (nucleoside-2':3'-cyclic-phosphate 2'-nucleotidohydrolase, EC 3.1.4.37) in whole mitochondria. Both inner and outer mitochondrial membranes showed increased (cyclic nucleotide)phosphohydrolase activity, but the inner was increased 94% compared to 67% for the outer. Techniques which disrupt membrane structure increased (cyclic nucleotide)phosphohydrolase activity. After these treatments, whole mitochondria from ethanol-treated animals still showed a 50% increase in activity. This increase may be related either to an inherent increase in the resistance of (cyclic nucleotide)phosphohydrolase to protein degradation or turnover, or to ethanol-induced membrane changes. An increase in (cyclic nucleotide)phosphohydrolase reaction medium pH was observed when freshly isolated, highly-coupled mitochondria were used. The total increase in pH was about 2-fold greater in the controls compared to the ethanol-treated mitochondria. It is suggested that the smaller initial increase in pH and the greater activity of (cyclic nucleotide)phosphohydrolase in the mitochondria from the ethanol-treated animals relate to previously observed changes in the lipid and protein composition of the mitochondrial membranes. In addition, (cyclic nucleotide)phosphohydrolase may represent an excellent marker for membrane integrity.
D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases / Q000378:metabolism*; D000818:Animals; D004140:Dinitrophenols / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000187:drug effects / Q000201:enzymology*; D007700:Kinetics; D008297:Male; D008930:Mitochondria, Liver / Q000201:enzymology* / Q000378:metabolism; D010085:Oxidative Phosphorylation / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D051381:Rats
D004140:Dinitrophenols; D000431:Ethanol; D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases; D010727:Phosphoric Diester Hydrolases