w2 nitrogen balance Flashcards
how is the majority of nitrogen is excreted from his body
urea
what urinary excretion products produced in the kidney would change in response to this metabolic condition
Ammonium
Administration of which of the following would be most beneficial in treating a child with a defect in the urea cycle
Benzoate and Phenylbutyrate interact with glycine and glutamine, respectively, and increase excretion
what explains an elevated BUN
Reduced excretion of nitrogen compounds
Which of the following dietary recommendations would be most beneficial in treating a chronic kidney disease patient’s azotemia ( high levels of nitrogen based compounds)
Decreased protein intake with sufficient carbohydrate
what is glutamine converted to in the kidney
ammonium
what is heme converted to
Heme is converted to bilirubin which is converted to urobilinogen
what role does alanine play in the liver
important in transporting amino acids from muscle to liver
what is the primary site for the urea cycle
liver mitochondria and cytosol
where do the N compounds for the urea cycle derive from
N contributed from aspartate and glutamate (see pic)
what process turns glutamate to ammonia
oxidative deamination
what process turns an alpha amino acid to an alpha keto acid
transaminase
describe the urea cycle
name 2 things that can increase the urea cycle
fasting and a high protein diet
what changes occur in arginine with CKD
Arginine: synthesized in kidneys from citrulline, precursor for NO, creatine, agmatine, other polyamines
CKD: other organs must synthesize arginine that would normally be made in kidneys
role of epo
Erythropoietin– stimulates the production of proerythroblasts from hematopoietic stem cells (increases the # of RBC’s in the blood in response to hypoxia)
Outline the main effects of erythropoietin on the red cell mass.
Red Cell Mass– the part of the total blood volume (BV) occupied by the RBCs
· Erythropoietin increases the red cell mass of total blood volume until sufficient oxygenation is restored, then the rate of erythropoietin production decreases to a lvl that maintains a good lvl of required # of RBC’s for adequate oxygenation to all tissue
So long as plenty of iron, Vit B12, and folic acid (with other nutrients) are available, the rate of RBC production can rise to ~10x or more
· When kidneys are unable to secrete erythropoietin, the quantity of RBC’s drops and severe anemia develops
o Few RBCs are formed by the bone marrow
o Liver can compensate for 1/3 of the RBC load, but not enough so anemia is inevitable
