Stimulation of Ethanol Metabolism by Catecholamines

Summary

The effects of catecholamines (epinephrine, phenylephrine, isoproterenol) on rates of ethanol utilization, oxygen uptake and glucose, lactate and pyruvate production from endogenous sources were studied in livers from fed rats perfused in a non-recirculating system.

The following results were obtained: (1) The infusion of catecholamines caused a rapid increase in the rates of ethanol utilization, oxygen uptake and glucose production which was fully reversed following the termination of the catecholamine infusion. (2) The increase in the rate of ethanol utilization was half-maximal at concentrations of 10⁻⁸M, 10⁻⁶M and 10⁻⁴M with maximal increases of 70%, 60% and 30% of control following the infusion of phenylephrine, epinephrine and isoproterenol, respectively. (3) The increase in ethanol utilization correlated with the changes in respiratory rates but not with the changes in rates of glycogenolysis. (4) The effects of epinephrine and phenylephrine on ethanol utilization, oxygen uptake and glucose production were totally abolished in the presence of phentolamine (10⁻⁴M), an α-adrenergic blocking agent. (5) In the presence of propranolol (10⁻⁴M), a β-adrenergic blocking agent, the effect of epinephrine on glucose production was decreased by more than 90%, whereas the effects on oxygen uptake and ethanol utilization were diminished only by 60%. (6) Glucagon and dibutyryl-cyclic AMP increased the rate of glucose production drastically but had no effect on ethanol utilization.

The data suggest that the stimulation of ethanol metabolism by catecholamines is secondary to the increased respiratory rate, which is independent of a mechanism mediated by cyclic AMP. Most likely, the increase in the rate of ethanol utilization is due to the α-adrenergic effects of catecholamines and could be mediated by calcium ions.