Cholesterol metabolism

What you will learn

• Distinguish free and esterified cholesterol and its structural and metabolic roles.
• Describe biosynthetic substrates, compartments, four stages, and the cholesterol synthesis balance.
• Explain HMG-CoA reductase regulation and the effects of statins, insulin, and glucagon.
• Compare ACAT, LCAT, and cholesteryl-esterase functions in storage, transport, and hydrolysis.
• Describe hepatic conversion to bile acids, their structure, functions, and enterohepatic cycle.

Course outline

1. Cholesterol, a sterol to distribute and control

   Understand why cholesterol is essential, where it comes from and how its flows connect intestine, liver, tissues and bile.

   20 min

2. Cholesterol structure and three transport pathways

   Recognize the amphiphilic framework and separately follow exogenous, endogenous and return flows.

   30 min

3. Preparing cholesterol biosynthesis

   Identify the tissues, compartments and resources required before following the four major construction phases.

   24 min

4. From acetyl-CoA to activated isoprenes

   Build mevalonate from three acetyl-CoA, then spend three ATP to form IPP and DMAPP.

   38 min

5. From isoprenes to cholesterol and pathway control

   Assemble six C5 units into squalene, form the steroid nucleus and regulate HMG-CoA reductase.

   38 min

6. Use, esterification and storage of cholesterol

   Follow LDL-receptor uptake, then distinguish the reactions of ACAT, LCAT and cholesteryl esterase.

   30 min

7. Bile acids: eliminating cholesterol and digesting lipids

   Understand their hepatic formation, structural changes and emulsification and micelle functions.

   36 min

8. Conjugation, enterohepatic cycle and elimination

   Follow bile salts from liver to intestine, their bacterial transformations, recycling and synthesis control.

   36 min