Determination of lipoprotein lipase activity in post heparin plasma of streptozotocin-induced diabetic rats by high-performance liquid chromatography with flourescence detection

The activity of lipoprotein lipase (LPL), responsible for lipoprotein metabolism, would vary in diseases and metabolic disorders. For determination of LPL activity, a highly sensitive high performance liquid chromatography (BPLC) method using a fluorescent reagent, 4-nitro-7-piperazino-2,1,3-benzoxadiazole (NBD-PZ) was applied to determinate the oleic acid (OA) generated from triolein by LPL activity without multiple solvents extraction step. We studied the optimal conditons of the reaction including the effect of emulsifiers, deproteinizing solvents, and the concentration of bovine serum albumin (BSA). Ten millimolar concentrations of triolein, 5% of BSA, 1% of Gum arabic (GA), and acetonitrile showed the optimum conditions for measuring the LPL activity. The accuracy values for the determination of LPL activity in 10 μL of rat post heparin plasma were 108.73-114.36%, and the intra- and inter-day precision values were within 1.28% and 2.91%, respectively. The limit of detection was about 4.53 nM (signal-to-noise ratio 3). The proposed method was applied to determination of LPL activity in post heparin plasma of normal and streptozotocin-induced diabetic rats associated with 52.3% reduction. The established assay system could be used for determining LPL activity in different physiological and pathological conditions to clarify the relationship between LPL activity and diabetes mellitus.