Ethanol intoxication stimulates lipolysis in isolated Golgi complex secretory vesicle fraction from rat liver

Ethanol (0.6 g/100 g) was administered orally to rats by means of an intragastric tube. This caused an accumulation of secretory vesicles laden with VLDL particles which were seen 90 min after administration and later disappeared. Lysosomes and Golgi complex secretory vesicle (GCSV) fractions were isolated. The proteolytic and lipolytic activities of these fractions were measured in order to assess their possible role in the elimination of the initially retained secretory material. There was no change in proteolysis neither in lysosomes or in the GCSV-fraction from ethanol-intoxicated rats when measured by the release of degradation products during incubation. Similarly, the activities of acid hydrolases were unaffected by acute ethanol intoxication. On the other hand, lipolysis increased by some 50-100% in the GCSV fraction, whereas the lysosomes displayed unchanged lipolytic levels compared with controls. Ultrastructurally, the GCSV-fraction from ethanol-intoxicated rat livers showed signs of disintegrated VLDL particles. It is concluded that acute ethanol intoxication causes an increase in lipolysis but not in proteolysis in the operationally defined GCSV fraction. Since triacylglycerol lipase activities did not change in the GCSV fraction, increased amounts of substrate seem to cause the enhanced lipolysis observed.