Triglyceride Assay Kits

Triglycerides (TGs) are compounds formed by the esterification of three fatty acid molecules with the hydroxyl groups of glycerol (glycerin). Triglycerides are also known as neutral fats or triacylglycerols and function as an energy source stored in the body, primarily in the liver and adipose tissue. The figure below shows tripalmitin, a triglyceride in which three molecules of palmitic acid are bound to glycerol. The properties of triglycerides vary depending on the hydrocarbon chain length of the fatty acids and the position and number of double bonds.

Triglycerides exist in the blood as lipoproteins. The density of lipoproteins varies depending on their composition. They are classified into chylomicrons, very low-density lipoproteins (VLDL), intermediate-density lipoproteins (IDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL) (Table 1). The sources of triglycerides in the blood include exogenous (dietary) and endogenous (synthesized in the body) triglycerides. Exogenous triglycerides are mainly found in chylomicrons, while endogenous triglycerides are mainly found in VLDL¹⁾. Chylomicrons are present in plasma after meals and are usually not present in the plasma during fasting²⁾. Conversely, VLDL is usually present in plasma in the fasted state²⁾.

In hyperlipidemia, the level of lipids in the serum, such as cholesterol and triglycerides, is increased. Hyperlipidemia is classified based on the increased lipid components³⁾. It is one of the risk factors for ischemic heart disease and cerebrovascular disease.

LabAssay™ Triglyceride is a kit based on an enzymatic colorimetric method (GPO-DAOS method) using the Trinder reagent. With the use of the enzymes and a microplate, this kit provides a convenient method for measuring triglycerides in samples.

Principle of the Triglycerides assay using GPO-DAOS method

Triglycerides in the sample are broken down into glycerol and fatty acids through the action of lipoprotein lipase (LPL). Glycerol is then converted into glycerol-3-phosphate by glycerol kinase (GK) in the presence of ATP. The resulting glycerol-3-phosphate is oxidized by glycerol-3-phosphate oxidase (GPO), simultaneously producing hydrogen peroxide. The resulting hydrogen peroxide induces oxidative condensation of 4-aminoantipyrine and DAOS through the action of peroxidase (POD), producing a blue dye. The absorbance of this blue dye is measured to determine the concentration of triglycerides in the sample.

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