CPRS 46: Metabolic Process of Renal Cortex and Medulla Flashcards
Consider Glucose
How would the following change with respect to the plasma glucose concentration?
- Filtration: Glucose is freely filtered, so the filtration rate ________ with plasma glucose level
- Reabsorption: ________ with plasma glucose level, until reaching a ____________. The threshold is called ________ (short form).
- Excretion: Reach a ________________ and then the excretion starts ____________ with plasma glucose level. The threshold is called _______ (short form).
Consider Glucose
How would the following change with respect to the plasma glucose concentration?
- Filtration: Glucose is freely filtered, so the filtration rate increases with plasma glucose level
- Reabsorption: Increase linearly with plasma glucose level, until reaching a maximum reabsorption threshold. The threshold is called TmG.
- Excretion: Reach a threshold and then the excretion starts increasing linearly with plasma glucose level. The threshold is called RTG.
If the plasma level of glucose is greater than ________ (which threshold), there will be glucose in urine.
If the plasma level of glucose is greater than RTG (which threshold), there will be glucose in urine.
*Beyond RTG = There will be excretion of glucose from the kidney tubules
Consider the Channels in Glucose Reabsorption
Reabsorption from the glomerular filtrate to the tubule epithelial cells. This is at the ________ membrane. The channels utilized are ___________ (10%) and __________ (90%).
Reabsorption from the tubular epithelial cells to the blood. This is at the ________ membrane. The channels utilized are __________ at the ______ proximal tubule; or __________ at the ______ proximal tubule. (fill in with early/late)
Consider the Channels in Glucose Reabsorption
Reabsorption from the glomerular filtrate to the tubule epithelial cells. This is at the APICAL membrane. The channels utilized are SGLT1 (10%) and SGLT2 (90%).
Reabsorption from the tubular epithelial cells to the blood. This is at the BASOLATERAL membrane. The channels utilized are GLUT1 at the LATE proximal tubule; or GLUT2 at the EARLY proximal tubule.
Consider Glucose Metabolism in the Kidneys
- Gluconeogenesis in the cortex: It needs (more/less) energy to activate. The activity is inhibited by _________, and increased by __________. Hormone _________ has no effects on this process.
- Glycolysis in the medulla: Needs (more/less) energy to activate
Consider Glucose Metabolism in the Kidneys
- Gluconeogenesis in the cortex: It needs MORE energy to activate. The activity is inhibited by insulin, and increased by catecholamine. Hormone glucagon has no effects on this process.
- Glycolysis in the medulla: Needs LESS energy to activate
Consider the release of glucose into the bloodstream
- Post-prandial (After meals).
- The release of glucose from kidney into blood is _____________ (increased/decreased).
- The release of glucose from liver to blood is __________ (increased/decreased) as _________ is being made from ___________. - Post-absorptive (Fasting).
- Release of glucose from _______ into the blood is about 25%. 50% comes from __________ and 50% comes from ___________.
- Release of glucose from _______ into the blood is about 75%. 100% comes from __________ and 0% comes from ______________. - Pathological conditions
- During liver diseases, there is increased glucose release from __________ to compensate liver dysfunction.
- During acidosis, there is increased glucose release from _________ and reduced glucose release from ________.
Consider the release of glucose into the bloodstream
- Post-prandial (After meals).
- The release of glucose from kidney into blood is INCREASED.
- The release of glucose from liver to blood is DECREASED as GLYCOGEN is being made from GLUCOSE. - Post-absorptive (Fasting).
- Release of glucose from KIDNEY into the blood is about 25%. 50% comes from GLUCONEOGENESIS and 50% comes from GLYCOGENOLYSIS.
- Release of glucose from LIVER into the blood is about 75%. 100% comes from GLUCONEOGENESIS and 0% comes from GLYCOGENOLYSIS. - Pathological conditions
- During liver diseases, there is increased glucose release from KIDNEYS to compensate liver dysfunction.
- During acidosis, there is increased glucose release from KIDNEYS and reduced glucose release from LIVER.
Consider Glutamine Metabolism in the proximal tubule cells in the cortex.
Which amino acid can usually be circulated in the liver?
In the proximal tubules,
Glutamine => _________ under enzyme _________
Glutamate => _________ under enzyme ________________
_____________ will become CO2 or glucose, the process is know as ______________.
In acidosis, compare the rate of Glutamine catabolism and Glutamine Reabsorption?
Glutamine _________ is more than that of Glutamine __________. Most Glutamine converted to __________ and ________ making the blood acidic.
Consider Glutamine Metabolism in the proximal tubule cells in the cortex.
Which amino acid can usually be circulated in the liver? Alanine
In the proximal tubules,
Glutamine => Glutamate under enzyme Glutaminase
Glutamate => Alpha-ketoglutarate under enzyme Glutamate dehydrogenase
Alpha-ketoglutarate will become CO2 or glucose, the process is know as gluconeogenesis.
In Acidosis,
Glutamine Catabolism is more than that of Glutamine Reabsorption. Most Glutamine converted to Glucose and CO2 making the blood acidic.
In pathological conditions like Diabetes Mellitus Patients, there will be increased reabsorption of glucose by building more ___________ channels.
In pathological conditions like Diabetes Mellitus Patients, there will be increased reabsorption of glucose by building more SGLT2 channels.
At Normal Filtration rate, the RTG = 11mM/L
During Chronic Kidney Disease, the RTG will be (smaller/larger) than 11mM/L
During Pregnancy/ Unilateral Kidney, the RTG will be (smaller/larger) than 11mM/L
Normal Filtration rate: RTG=11mM/L
During Chronic Kidney Disease, the RTG will be LARGER than 11mM/L
During Pregnancy/ Unilateral Kidney, the RTG will be SMALLER than 11mM/L
