LPL and obesity due to melanocortin 4 receptor deficiency: Another study showed that ANGPTLs 3 and 4 control lipid metabolism by inhibiting the activity of lipoprotein lipase (LPL) [47], an enzyme responsible for hydrolysis of triglycerides (TG) contained in lipoproteins, such as chylomicrons and very low-density lipoproteins (VLDL), fatty acids, and cholesterol, whereas ANGPTL6/AGF antagonizes obesity and related metabolic diseases, including insulin resistance, by enhancing systemic energy expenditure [45].