Lipids 4: Cholesterol and steroid metabolism

There is one chapter for suggested reading from Lippincott, Chapter 18: Cholesterol, Lipoprotein, and Steroid Metabolism. The short descriptions and videos listed below are some of the big-picture, high-yield points. The reading and the class session will go into more depth and detail. The reading guides are also posted.

As I have said in other modules, this reading guide is for people who have difficulty focusing on these types of chapters. Most students DO NOT need to use the guide.

Cholesterol, Lipoprotein, and Steroid Metabolism. Lippincott® Illustrated Reviews: Biochemistry, 8e. Medical Education: Health Library.

Cholesterol and Steroid Metabolism is covered in Chapter 18. 

Cholesterol: Structure, synthesis, and degradation 

• What is cholesterol? (Fig. 18.2) Where is it synthesized? What are sterols and cholesteryl esters? (Fig. 18.2) 

• How is cholesterol made? What is HMGCoA? (Fig. 18.3) What is mevalonate and why is it important during the synthesis of cholesterol? (Fig. 18.4) Be able to identify how the following are important in cholesterol synthesis: IPP, DPP, GPP, FPP, squalene, lanosterol, and cholesterol.  What enzymes are important? (Fig. 18.5) 

• How is cholesterol synthesis regulated? Gene expression? Sterol-accelerated enzyme degradation? Phosphorylation/dephosphorylation? Hormonal regulation? (Fig. 18.6) 

Bile acids and bile salts 

• What are bile acids? (Fig. 18.8) Bile salts? (Fig. 18.9) How are they synthesized? How are they circulated from the liver? (Fig. 18.11) What is Cholelithiasis? Why does it occur?  What are the outcomes? Is there a treatment available? 

Plasma lipoproteins 

• What are plasma lipoproteins? What are VLDLs? What are LDLs? What are HDLs?  What are chylomicrons? How are these different lipoproteins different? How are they similar?  What are apolipoproteins and how do they relate? (Fig. 18.13, 18.14, and 18.15) 

• Explain the metabolism of chylomicrons; including the synthesis, assembly, modification, and the degradation of TAGs by lipoprotein lipase and its regulation. (Fig. 18.16) 

• Be able to explain the metabolism of VLDL; including the release, modification and production of LDL. (Fig. 18.17) 

• Be able to explain the metabolism of LDL. How does it fit into endocytosis (and why is this important)? Be able to explain this endocytosis and why it is important. How do macrophages take up LDL? (Fig. 18.22) 

• Be able to explain the metabolism of HDL. How does it relate to apolipoproteins? How does it uptake unesterified cholesterol? How does it esterify cholesterol? (Figure 18.23) What is its role in cholesterol transport? 

• What is the role of lipoprotein (a) in heart disease? 

• Identify the following: apoA-I, Lipoprotein lipase (LPL), apoB-48, apoB-100, apoE, LCAT, ACAT.

Steroid hormones 

• How are steroid hormones synthesized? (Fig. 18.25) How are they secreted from the adrenal gland? What are the different types of adrenal cortical steroid hormones? How are hormones secreted from the gonads? (Fig. 18.27) What is the mechanism of action of steroid hormones? (Fig. 18.28) 

Describe the structure, synthesis, and degradation of cholesterol and the control of these processes

• HMG Co A Reductase 

• Cholesterol synthesis 

• Statins 

Describe the synthesis and function of bile acids and bile salts 

• Cholesterol-7-alphA-hydroxylase 

• Enterohepatic circulation of bile 

• Bile salt and acid synthesis 

• Cholelithiasis 

• Cholestyramine 

Describe the metabolism of chylomicrons, very-low-density lipoprotein (VLDL), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and explain how these lipoproteins impact health 

• ApoA1 

• ApoB 

• ApoE 

• ApoCII 

• LCAT 

• ACAT 

• CETP 

• HDL 

• LDL 

• VLDL 

• Chylomicrons 

• Lipoprotein lipase 

• familial hypercholesterolemia, FH 

• Abetalipoproteinemia 

• Atherosclerosis 

Describe how steroids are synthesized and utilized by the body 

• Desmolase