Lecture 33: Absorptive and Postabsorptive nutrient utilization Flashcards
What is the origin of glucose in the absorptive phase/ Phase I of glucose homeostasis
Exogenous
What tissues are using glucose in absorptive phase/phase 1 glucose homeostasis
All
What is the major rule of the brain during absorptive phase/phase 1 glucose homeostasis
Glucose
What is the origin of blood glucose in postabsorptive/phase 2 glucose homeostasis
Hepatic glycogen, gluconeogenesis
What tissues are using glucose during postabsorptive/phase 2 glucose homeostasis
All except liver, muscle and adipose at diminished rates
What is the major fuel source to the brain during postabsorptive/phase II glucose homeostasis
Glucose
What is the origin of blood glucose in phase III/prolonged energy deficiency
Hepatic and renal gluconeogenesis
What tissues are using glucose during phase 3/ prolonged energy deficiency stage
Brain and RBC’s, small amount by muscle
What is the major fuel of the brain during phase 3/prolonged energy deficiency
Glucose, ketone bodies
What is the origin of blood glucose in phase IV/ prolonged energy deficiency
Renal and hepatic gluconeogenesis
What tissues are using glucose in phase IV/ prolonged energy deficiency
Brain at a diminished rate, RBC’s normal
What is the major fuel of the brain in phase IV/ prolonged energy deficiency
Ketone bodies, glucose
Why does glucose concentration need to be controlled tightly
Major fuel source to the brain
During the absorptive phase what is the depot site for glucose and AA
Liver
During absorptive phase what is the depot site for TG/FA
Liver, adipose tissue
What are the 3 metabolic pools
- Glucose
- FA
- AA
What is the substrate in Kreb cycle
acetate
Glucose stored as
Glycogen
What is the first step in processing of glucose
Glycolysis
Excess glucose can be converted to ___ in the liver
FA
How is glucose converted to FA in liver
- Glucose—> pyruvate
- Pyruvate and oxloacetate—> citrate
- Citrate—> acetyl coA and oxaloacetate
- Acetyl CoA to FA
- Oxaloacetate to pyruvate
What is the transport amino acid
Alanine
How is alanine formed
Nitrogen—> pyruvate—> alanine
Most AA enter circulation and are channeled through ___
Liver
Amino acids are delaminated which produce ___ and ___
Ketoanalogues and urea
Liver selectively removes AA that can be used for ___ or ___
Protein synthesis or liver metabolism