Heme Degradation and Jaundice Flashcards
Objectives: Hemedegradation and jaundice •Outline the steps in the degradation of hemeto bilirubinin the macrophages. •Explore the relationship of serum albumin and the transport of bilirubin •Explain the biochemical consequence of a block in each of the steps in the uptake and conjugation of bilirubinin liver. Distinguish the activity of UDP-glucuronyltransferasein adults versus premature babies. •Analyze the steps in the processing of conjugated bilirubinin the intestine and its excretion
What is the enzyme that begins heme degradation?
Heme Oxygenase
What transports bilirubin in the blood?
Albumin
What three drugs displace bilirubin from albumin in the blood?
Salicylate
Asprin
Sulfanomides
Once bilirubin is within the hepatocyte, what does it bind to?
Ligandin (intracellular protein)
What is used to conjugate biliruibin?
UDP-glucuronic acid
What is another name for conjugated bilirubin?
Bilirubin diglucuronide
What is defective in Dubin-Johnson syndrome?
MRP2 transporter (ABC transporter) that transports conjugated biirubin from the hepatocyte into the biliary caniliculus.
Why are the feces of newborns of a clayish gray color?
There is no urobilinogen in the gut of fetuses and urobiligen is what leads to stericobilinogen (which leads to brown color)
(T/F) Bilirubin is covalently bound to albumin
False
What reagent is used in lab tests to detect conjugated bilirubin?
Diazo reagent
Which enzyme deficiency leads to the physiological jaundice of the newborn?
Bilirubin UDP-glucuronyl transferase
What is the clinical sign of jaundice?
Yellowish discoloration of the:
skin
mucous membranes,
sclera
and nail beds
(due to: bilirubin binds to connective tissue)
How is posthepatic Jaundice different from
Post: no increase in unconjuated bilirubin
What is the injury marker for complete obstructive jaudice?
serum ALP
color of urine is orange/reddish/brown
