Bilirubin metabolism

عالء الدين

Warning: Audience discretion is advised,

what you are about to see is a true story

about the miserable life of bilirubin.

Translated into English from an Arabic version from a King Saud University parody

Lecture.

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• Inside the vessels of a human

• In the bottom of heart

• There was a loving family called „‟

Hemoglobin‟‟ living.

• In a simple house called „ RBC „.

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• Consist of a father called „‟ ProtoPorphiren” who has a brownish colour.

• Madame „‟ Globin‟‟ who is from a protein origin

• Four sons are called „‟ Iron „‟.

In 120 daysعالء الدين

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hemolysis

• The villian called „‟ReteculoEndothelial System’’ sweeps off the house because it was over 120 days of age.

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And the life of the happy family

changes

)= And becomes sadعالء الدين

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Haemoglobin is cleaved into haem & Globin which is hydrolysed into free AA

• Globin asks for divorce to get back to her family

house „‟ Amino acid pool‟‟.

طلقنى طلقنى

..طلقنى

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And every iron gets into his automobile

„‟Transferrin‟‟ and travels far away.

Bye Daddy!!…

Iron is carried on transferrin to be reused

)= Dad becomes lonely and sadعالء الدين

عالء الدينHis colour changes to green and people called him

„‟ Biliverden‟‟

Protoporpherin is then reduced into Biliverden

عالء الدينThen his name changes to the infamous yellow

colour called „‟Bilirubin‟‟

Then into Bilirubin

عالء الدينHis friends convince him to tie the knot again.

They propose Mademoiselle „‟ Albumin‟‟ to him.

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Indirect bilirubin is water insoluble

• But Mademoiselle „‟ Albumin „‟ wanted to know

him better before getting married.

I heard that you are

‘’ indirect’’, I

wanna know ya

more before we

marry!.

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so it is carried on albumin and called haemobilirubin or indirect bilirbin

•So some people believe they got married

Darling, people think we are married;

tell them we are just „‟ engaged‟‟.

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Or unconjugated bilirubin

They get called „‟haemobilirubin”

•“indirect bilirubin”

•“unconjugated bilirubin ”

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Indirect bilirubin cannot be filtrated from the kidney even in it‟s exess so not present in urine in

haemolytic jaundice “acholuric”

• But Indirect billuribin cannot enter the kidney even if it was in an ample quantities because it is toolarge.

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و

Whaddaya

think of dat

house dear?

Oh dear, I would never live in

such a house, it‟s a factory

not a house. So big!!

So Bilirubin decides to live in the liver, but Mrs.

Albumin refuses.

عالء الدين• They split up

The sad bilirubin enters the „liver‟

Farewell darling

=(

•عالء الدين In the liver; Bilirubin meets with two hawt blue

ladies.

What are your

names my blue

angels?

Glucuronic

acid

Marry me?

Indirect bilirubin is conjugated in the liver with 2 glucuronic acid molecules

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Glucuronyl transferase

• The enzyme „‟Glucuronyl transferase „‟ wed them*.

• His name changes to Direct or Conjugated or Cholibilirubin

Now it is termed Direct or Conjugated or Cholibilirubin

Enzyme

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Conjuged bilirubin can be filtrated in urine if it is increased as in obstructive & hepatocellular jaundice

The cool thing about you

girls; you are so cute and

small we can enter the „‟

kidney‟‟ easily.

We better go to the

„‟ Small intestine‟‟

whaddaya think?

I don‟t know the

directions, I should

ask one of my buds

to lead me there.

عالء الدين

Ladies, this is

Mr. „Bile Salts‟

Let‟s go fellows, Bile

to go!!

عالء الدينAll of them went to the small intestines through

But something unexpected happenedbile.

Direct bilirubin (Bile pigment) is secreted into bile with bile salts

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Intestinal bacteria remove glucuronides and reduce bilirubin into stercobilirubin

• Bacteria attacks! Bilirubin lost their wives and

became a widow called “stercobilinogen”

عالء الدين• So Stercobilinogen decided to go back to blood and get

absorbed with the nutrients.

Some of it is reabsorbed and go to the liver

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While some remain and become oxidized to stercobilinogen

• Others were pessimist and decided to die by oxidisation, so they went along the ‘’stool’’ and are called ‘’Stercobilin’’

• They give the stool its dark colour.

عالء الدين• But the part that went to the liver divided into two

groups

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A fraction of the absorbed part become excreted again into bile“Entero-hepatic Ciculation”

Some went again through bile in a circulation called ‘’ Entero-hepatic Circulation’’.

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Some go to the kidney and excreted as urobilinogen which is oxidized into urobilin

A group went to the kidney, excreted with urine as Urobilinogen which oxidses into urobilin.

.This was the ending of bilirubin‟s lifeعالء الدين

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stool

Urine

Blood

Sterco

bilinogen

Summary

Entero-

hepatic

circulation

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Urine

stool

Blood

Sterco

bilinogen

Haemolytic

jaundice

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Urine

stool

Blood

Sterco

bilinogen

Hepatocellular

jaundice

indirect

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Urine

stool

Blood

Obstructive

Jaundice