Simplified analysis of lipoprotein lipase activity: Evaluation of lipasemic activity of low molecular weight heparin in rats

A simple procedure for measuring lipoprotein lipase activity was developed by using newly formulated substrate with turbidimetry method. The activity of lipoprotein lipase was expressed as Yvalue (%) that was calculated by measuring UV absorbance (600 nm) at two time points (30 sec and 15 min). Lipid emulsions as the substrate and other factors affecting the lipolytic activity of lipase were studied. The optimal conditions for an in vitro experiment were found to be with LIPOMCT® as lipid substrate at 37°C in tris-HCl buffer (pH 7.4) in the presence of BSA. To evaluate an in vivo applicability, low molecular weight heparin (LMWH)-containing drug, Sulodexide ®, was administered to the rats. The serum from LMWH-administered rats was incubated in an optimized analytical condition without BSA. As expected, increasing the amount of LMWH administered led to higher lipase activity. The newly developed method was successfully applied to an in vivo model suggesting the potential to be applicable for the pharmacodynamic studies of commercially available products of LPL analogues in human subjects, and for the diagnosis of acute pancreatitis in the clinical laboratory.