Heme Degradation

Question 1

I like to divide lectures into categories. The heme degradation lecture can be divided into three categories

Answer 1

(1) Heme metabolism (Heme –> unconjugated bilirubin)
(2) Conversion of unconjugated bilirubin conversion to conjugated bilirubin
(3) Metabolism of conjugated bilirubin
(two fates - reabsorption or excretion)

Question 2

What is the Van den bergh reaction?

Answer 2

A coupling of bilirubin with a diazonium salt to form a colored complex

Question 3

Direct =

Answer 3

conjugated

Question 4

Indirect =

Answer 4

unconjugated

Question 5

What compound does biliverdin reductase require?

Answer 5

NADPH

Question 6

Describe the conjugationof biliruubin?

Answer 6

Bilirubin is conjugated to glucoronic acid in the liver

Question 7

What is Gilbert?

Answer 7

reduction in transcriptin of HDP-GT due to a mutation in the promoter region

Question 8

What is Criggler-Najjar Syndrome: Type-1?

Answer 8

Complete absence UDP-GT gene

Question 9

What is Criggler-Najjar Syndrome: Type II?

Answer 9

Mutation in UDP-GT

Question 10

What is Dubin-Johnson?

Answer 10

Mutation in MRP2

Question 11

What is Rotor?

Answer 11

Biallelic inactivating in OAT1B1 & OAT1B3

Question 12

Which compound produced by intestinal bacterial degradation of
conjugated bilirubin gives its yellow color?

Answer 12

Urobilinogen (colorless) but is converted to Urobilin (yellow color of urine) in the kidney

Question 13

What type of hyperbilirubinemia results from cholestasis?

Conjugated vs Unconjugated

Answer 13

Cholestasis is defined as a decrease in bile flow due to impaired secretion by hepatocytes or to obstruction of bile flow through intra-or extrahepatic bile ducts. Therefore, the clinical definition of cholestasis is any condition in which substances normally excreted into bile are retained. The serum concentrations of conjugated bilirubin and bile salts are the most commonly measured.