Organ metabolism L62 Flashcards
How is the gene expression regulated in Different organs?
Epigenetic regulation:
1) DNA methylation: decrease DNA transcription
2) Histone acetylation and Phosphorylation: increase transcription
3) Different Transcription factors in Different muscles
What are important functions of the kidney?
1) Renin which controls BP and Na metabolism though Renin-Angiotensin
2) Produces erythropoietin (glycoproteins) increase erythropeosis = making of RBC
3) Hydroxylation -> activation of Vitamin D
4) Controls the content of the ruin
What might happen if we have a kidney dysfunction?
1) Anemia
2) BP problems
3) Vit D deficiency
4) Urine composition problem (ex: Cystinuria)
5) Kidney Stones
What is in kidney stones
1/2: Ca oxalate (increased diet in oxalate causes kidney stones ex: spinach)
1/3: CaPO4 or CaCO3 or MgNH4PO4 or association
Cystein in Cystinuria
Uric Acid Stone in Gout (increased Purine metabolism -> uric acid > s) -> kidney stones and deposition in joints
What can the urine composition tell us?
1) Diabetes
2) Problems w/ amino acids/ proteins bc we should have none in the urine
3) How the pH was balances (NH4+ in the urine gets rid of H+ in the blood)
4) Creatinine comes from creatine Phosphate in muscle, more muscle mass (men), more creatinine
5) Phosphate and Sulfate reflect protein metabolism
What is a good kidney function test?
Observe levels of creatinine in the kidney
What are some functions of the liver?
1) control CHO metabolism
2) Control lipid metabolism
3) Drug and Hormone metabolism
4) Blood and plasm protein synthesis
5) Formation of Bile
6) N balance
What is so special about the liver as an organ
Ability to regenerate after a partial hepatectomy
How long after a complete hepatectomy would the pt die?
24 h
What does it mean if we have glucose in the urine?
diabetes
How can the kidney control pH of the blood?
1) gets rids of H+ as NH4+
2) Can make HCO3-
Why is the liver important in N balance?
Because the last step of the amino acid metabolism which ends up in putting the N on the urea happens in the liver
What happens in the N balance in the liver is dysfunctioning
Urea is not made
- -> Ammonia would accumulate
- -> Hepatic Encephalopathy/ coma due to hyperamonemia
How is the liver involved in the metabolism of CHO?
1) Glycogen storage
2) Glycogen degradation
3) Gluconeogenesis
How is the liver involved in the metabolism of lipids?
FA oxidation
FA synthesis
But FA oxidation -> Acetyl CoA
if ACoA»_space; TCA
we make KB but liver cannot metabolize KB bc it lacks Acetoacetate-Succinate CoA transferase so it gives it to the muscles -> happy
Liver= Altruistic
How is the liver involved in lipids other than FA?
Cholesterol
Packaging and storing
How is the liver involved in bile production?
Cholesterol
-> bile acids
Bile acids + Gly or taurine -> Bile salts which emulsify fats
bile = Bilirubin diglucunoride + Bile esters
What diseases are involved in problems w/ Bilirubin Conjugation?
1) Dubin-Johnson syndrome: no removal of bilirubin
2) Crigler-Najjar: no glucunoridation of Biliirubin
- > Liver Test
How is the liver involved in drug metabolism?
1) phase 1: Cytochrome P450s which are dose sensitive to the drugs and that happens in ER
2) Conjugation reaction w/ sulfate and glucorunic acid
For ethanol: metabolized by ethanol dehydrogenase which uses NAD and which is constitutive so it is not regulated
ethanol can also be metaboliszed by P450 2E1
Ethanol ->acetaldehyde -> acetate (which is tolerable)
What happens in the liver of alcoholics?
We cannot upregulate ethanol dehydrogenase so the P4502E1 can help
but NAD:NADH goes up since we use ethanol dehydrogenase more
Accumulation of acetaldehyde
-> toxic
-> cirrhosis (fibrous tissue replaces hepatic tissue)
How is liver involved in the plasma protein making?
1) Fibrinogen
2) Albumine (osmotic pressure)
3) Alpha and Beta Globuline
4) Prothrombine (blood clotting time)
What happens in the event of plasma protein dysfunction?
1) blood clotting time extended
2) Osmotic pressure misbalance and then edema and think about Kwashiorkor when there is not enough aa to make these plasma protein
What are the test of liver CHO metabolism?
1) glucose tolerance: we give a person a solution of glucose and then we see how their glycemic will be a high glycemic might be caused by DM or liver damage to store glycogen
2) IV galactose tolerance
What is the test for liver lipid metabolism?
Cholesterol esterification to make cholesterol ester where OH on position 3 is esterified
Liver damage -> different levels of cholesterol:cholesterol ester
