Changes in the composition and physico-chemical characteristics of serum lipoproteins during ethanol-induced lipaemia in alcoholic subjects.

The effect upon serum lipids and lipoproteins of a large intake of ethanol (180 g in 6 hr) has been studied during the ensuing 24 hr in 21 subjects. These were all men who were habituated to heavy drinking but who were shown to be normolipaemic when maintained on a normal diet with a restricted intake of alcohol. In all the subjects studied, ingestion of this amount of ethanol induced an acute hypertriglyceridaemia which varied in intensity between individuals, with increases ranging from 26% to 377% above the basal value. On the other hand, no significant change occurred in plasma cholesterol. In addition to measurements of triglycerides and cholesterol, the plasma from all the subjects were examined by electrophoresis in agarose and polyacrylamide gels with photometric scanning of the gels. In a subgroup of ten of the subjects, the plasma lipoproteins were separated into very low density (VLDL), low-density (LDL), and high-density (HDL) fractions, which were also analyzed biochemically and by electrophoresis. Following ethanol ingestion, a mean increase of about twofold in triglyceride content, and a decrease in the cholesterol/triglyceride ratio was observed in VLDL, LDL, and HDL. The triglyceride/protein ratio decreased in VLDL and increased in LDL. On electrophoresis of the intact sera following ethanol ingestion visible particulate fat and a band which failed to permeate the gel ('chylomicron-like band') was observed in five out of ten subjects and eight out of these ten subjects showed a prominent prebetalipoprotein (pre-beta) band. This component was found to be present in the lipoprotein fraction of density greater than 1.006 Kg/1. Examination of this fraction from basal specimens revealed a pre-beta band in only two of the ten subjects and the intensity of this band increased in the corresponding fractions from the same subjects after ethanol ingestion. In an additional four subjects no pre-beta was detected in this fraction before ethanol but appeared after ethanol ingestion. No attempt has been made to characterize further the component with these characters but it is suggested that it is probably an intermediate lipoprotein (ILDL), that is, a lipoprotein with characteristics intermediate between VLDL and LDL.