stiner- liver Flashcards
the majority of plasma proteins are made where?
liver
example of plasma proteins
- coagulation factors
- albumin
- acute phase proteins
acute phase response
systemic changes which occur in response to infection or inflammation
CRP
a major component of the acute phase response and a marker of bacterial infection.
Genetic deficiency of ≈________ presents in infancy as liver disease or in adulthood as lung disease
α1-antitrypsin
Genetic deficiency of_______ leads to Wilson’s disease, a condition associated with liver and CNS damage
ceruloplasmin
Liver cancer is associated with particularly high plasma concentrations of ________
α-fetoprotein
how are plasma proteins and membrane receptors degraded in the liver?
endocytosed and then hydrolyzed by acid proteases within intracellular organelles known as lysosomes.
how are intracellular proteins degraded in the liver?
are degraded within structures known as proteasomes by the so-called ubiquitin-proteasome system .
ubiquination, how many? how many enzymes involved?
5 or more molecules. 3
Catabolism of amino acids generates what two things?
ammonia (NH3) and ammonium ions (NH4+).
what happens to Most ammonia at its site of formation,?
detoxified by amidation of glutamate to glutamine
glutamate is mainly derived from where and used by what cells
muscle, enterocytes
what happens to the remaining nitrogen? enters as what?
enters the portal vein either as ammonia or as alanine, both of which are used by the liver for the synthesis of urea
main nonerythocytic site of heme production?
liver
starting components for heme synthesis
glycine, succinyl-CoA
step 1 in heme synthesis by what enzyme? where?
starting components —> 5 ALA by 5-ALA synthase
in mitochondria, rate limiting step
step 2
2 5 ALA molecules condense to form PBG
step 3
four PBG molecules combine to form a linear tetrapyrrole compound, which cyclizes to yield uroporphyrinogen III and then coproporphyrinogen III.
step 4
decarboxylation and oxidation of side chains in uroporphyrinogen III yield protoporphyrin IX.
step 5, final
iron (Fe2+) is added by ferrochelatase to protoporphyrin IX to form heme
what controls the rate of synthesis and what does it act on?
heme, 5ALA synthesis
when oxidized bilirubin becomes what?
biliverdin
bilirubin main physiological role?
cellular antioxidant
Bilirubin is excreted in what and what?
bile and urine
3 main causes of jaudance
prehepatic, intrahepatic, posthepatic
how are drugs metabolized
increases the hydrophilicity of drugs and therefore their ability to be excreted.
metabolites that are produced are less pharmacologically active than the substrate drug
some inactive prodrugs are converted to their active forms as a result of liver processing.
phase 1 of drug metabolism? by what?
addition of polar group, cytochrome P-450 (CYP)
phase 2 of drug metabolism
conjugation
