Validation of a stable emulsion for the assay of lipoprotein lipase activity

The preparation of a stable, stock, radioactive, trioleoyl glycerol emulsion in glycerol and its application to the assay of lipoprotein lipase are described. The data presented indicate that this stock emulsion combines the convenience and reproducibility of commercially available, nonradioactive emulsions with the sensitivity of sonicated, radioactive, aqueous emulsions. Furthermore, in practice, this glycerol-based emulsion appears to be specific for the protamine-sensitive extrahepatic lipase, having little or no reactivity toward the hepatic lipase measured in postheparin plasma.