Effect of ethanol on glycerol metabolism in rat liver during different hormonal conditions

Abstract

The effect of ethanol on the metabolism of glycerol and its regulation was studied in rat liver in vitro, under different hormonal conditions. Glycerol utilization by normal rat liver slices is inhibited to about 50 per cent upon addition of ethanol. Ethanol addition to normal animals increases hepatic concentrations of α-glycerophosphate and 5'AMP, which have been observed to inhibit hepatic glycerokinase. Glucagon administration to normal animals also causes an increase in hepatic α-glycerophosphate and 5'AMP content and consequently lowers glycerol utilization. Insulin administration neither effects α-glycerophosphate, AMP content, nor the rate of glycerol utilization. In alloxan diabetes, although α-glycerophosphate concentration is lowered, glycerol utilization is not different from normals as hepatic AMP concentrations are doubled. Blocking ofglycolysis by 2-deoxyglucose-6-phosphate lowers ethanol mediated accumulation of α-glycerophosphate in insulin and glucagon treated groups. Ethanol addition causes an increase in glycerol release from all groups, except that treated with insulin. The activities of hepatic glycerokinase and α-glycerophosphate dehydrogenase in the insulin treated or diabetic groups are not different from the control group. This investigation shows that an increase in either of the two inhibitors of glycerokinase, namely aglycerophosphate, or 5'AMP can result in an inhibition of hepatic glycerol utilization.