Influence of oleic acid on serum lipoprotein-X in vitro.

Lipoprotein-X is no longer detectable in serum by either the agar gel-electrophoresis/polyanion precipitation technique or immunoelectrophoresis with specific antiserum after in vitro addition of oleic acid. Evidence is presented which indicates that this ostensible loss is due not to its destruction, but rather to altered electrophoretic mobility. The findings suggest an explanation for the well known post-heparin "disappearance" of lipoprotein-X, and indicate that caution may be needed in the interpretation of such lipoprotein-X testing of sera from subjects with increased concentrations of lysolipids in their blood.