Block 3: 13: cholesterol derivatives

Question 1

1.Describe the major steps in the biosynthesis of bile acids by the liver
-where does it happen?
classical vs alternative/acidic pathway
-what are the general steps?
-concept?
-what is the enzyme of importance?
what is it inhibited by?
what are the 2 major bile acids produced?
how do they enter enterocyte?

Question 2

Describe the formation of bile salts and secondary bile acids and

explain the physiological importance

-describe evolution from bile acid to bile salt and then secondary bile acid.

Question 3

Define enterohepatic circulation and

explain its importance in bile acids metabolism

Question 4

Describe formation of bile and explain the mechanisms leading to gallstones formation
-what is the importance of PL?
-what lipid is not included in bile?
-how are gallstones formed?
-what is cholelithiasis?
treatment?

Question 5

why did guy who ate 15 eggs a day still have normal plasma cholesterol levels?

Question 6

Name the major classes of steroid hormones,

their localization and general physiological function

• common precursor?
• what is steroidogeneiss?
• what 2 enzymes are used?
• what is aromatase?

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Question 7

describe interconversion of cortisol to cortisone
which is active?
functional groups?
type 1 vs type 2?

Question 8

Explain the mechanisms by which the trophic hormones

regulate acute steroidogenesis

• first step of steroid genesis?
• location?