What happens to IDL particles after VLDL donates fatty acids?

• A. Excreted in urine
• B. Converted to HDL
• C. Remain as IDL indefinitely
• D. Some are removed by the liver, others become LDLs

Answer: (D)

After VLDL donates fatty acids, it becomes IDL, a transitional particle that can follow one of two main paths. The liver can clear IDL directly by recognizing apoE on the particle and taking it up via liver receptors. Alternatively, hepatic lipase can act on IDL to remove more triglycerides and enrich the particle in cholesterol, converting it into LDL. So, some IDL is removed by the liver, and others become LDLs. This is why excretion in urine doesn’t occur and IDL doesn’t stay the same indefinitely.