Hepatic adenosine in rats fed ethanol: effect of acute hyperoxia or hypoxia

The level of adenosine was measured in monthly biopsied livers from rats fed ethanol and a high fat/low protein diet in order to test a hypothesis that hepatic adenosine is increased due to enhanced breakdown of adenine nucleotides in which ATP and total adenylate pool were decreased by chronic ethanol feeding. The ethanol-fed rats showed a significantly higher average level of adenosine compared to the pair-fed controls. When investigated monthly, however, adenosine in ethanol-fed rats increased only after the decrease in ATP had stabilized and AMP remained unchanged, indicating that these changes were not temporarily related. The average percentage of change in adenosine after acute hyperoxia or hypoxia were variable both in ethanol-fed and pair-fed rats. There was a tendency for a positive correlation between the percentage of change of adenosine and AMP after hyperoxia regardless of ethanol feeding. A negative correlation between the percentage of change of adenosine and energy charge, and a positive correlation between the percentage of change of adenosine and AMP were seen after hypoxia regardless of ethanol feeding. Adenosine levels changed rapidly in response to changes in systemic of pO2 in both the ethanol-fed and control rats, indicating that the liver maintained its normal response to the changes in energy state. The results indicate that chronic ethanol feeding does increase the level of adenosine in the liver and that this level remains responsive to acute changes in pO2.(ABSTRACT TRUNCATED AT 250 WORDS)