Flashcards in Lecture 39 Deck (30):
True or False:
There is always a high metabolic demand for ATP use?
False: there is variable metabolic demand for ATP
What happens to insulin and glucagon as blood glucose levels rise (after a meal)?
Insulin is increased and Glucagon is decreased
-Insulin:glucagon ratio increases
Because ruminants convert CHO in their diet to VFA's they require _____ to make glucose to fuel brain and RBCs.
*In these animals glucagon is released after a meal
How is insulin secretion different in ruminants from other mammals? What is it maintained by?
-Insulin secretion in ruminants continues after the meal has been digested (maintained)
- amino acids, glucagon, GI hormone stimulation
In the well-fed state what happens to the glucose once it reaches liver?
-Either stored as glycogen or converted to fat through lipolysis
What organs require glucose for energy?
Brain, Kidney, Liver, RBC, Muscle
___ works to drive liver glucose uptake when blood glucose is ____
What happens to glucose in adipose tissue following a meal?
-Used for glycerol 3-phosphate production for TG storage
Following a meal the Insulin driven anabolic pathways are ____, while the glucagon-driven catabolic pathways are ____.
Following a meal protein phosphatases are ____ and protein kinases are ____
Indicate increase/decrease or on/off following a meal:
1. GLUT4 translocation
3. Glycogen Synthase
4. Glycogen phosphorylase
6. PFK II
8. Fructose 2,6 bisphosphate
6. actively phosphorylating Fructose 2,6 P2
What is responsible for delivering lipids to tissues for use and storage?
Indicate what effect high insulin is having on the following pathways:
2. Acetyl CoA carboxylase
3. Lipoprotein Lipase
4. Hormone Sensitive lipase
2. On --> convert excess glucose to lipid
3. On --> deliver FA for storage
4. Off --> prevents TG breakdown
True or False:
Liver metabolizes aromatic amino acids and non-hepatic tissue metabolizes branched chain amino acids.
Please indicate whether the rate of the pathway would be increased or decreased when the two conditions are compared.
1. Glucagon secretion in a Fasted state is ___ relative to the well fed state
2. Liver glycogen synthase activity in the well-fed state is ___ relative to a fasted state
3. Liver glycogen phosphorylase activity in a fasted state is ___ relative to the well-fed state
4. Muscle protein synthesis in the well-fed state is ___ relative to a fasted state
5. Adipose tissue lipolysis in a fasted state is ___ relative to a well-fed state.
Is there more energy in stored glycogen or stored triglyceride?
In the early fasting state what does the liver release?
Glucose from the glycogen supply
In early fasting liver glycogenolysis ____
-Brain and RBC need glucose!
In general what is the glycogenolysis pathway?
Glucagon --> PKA --> activated phosphorylase kinase --> Glycogen phosphorylase --> Breakdown glycogen
When the insulin:glucagon ratio falls sufficiently during mid fasting liver ___ is increased as well as adipose tissue ____
How does the liver promote gluconeogenesis during mid fasting?
-Glucagon activates liver PFK II phosphatase which decreases fructose 2,6 P2, turning gluconeogenesis on
How is lipolysis activated during mid fasting?
-Glucagon and epinephrine activate hormone sensitive lipase
What is the significance of lipolysis activation during mid fasting?
-Provides FFA for tissues to oxidize and allow diminished glucose oxidation
During late fasting/early starvation where is the glycerol coming from for gluconeogenesis?
-Glycerol is released from adipose tissue lipolysis which is activated by catecholamines and cortisol
How does the glucose requirement change during early and intermediate-late starvation?
Early on glucose requirement is high but later the brain can switch to using ketones so gluconeogenesis decreases and ketogenesis increases
True or False:
The liver is the only organ that can perform gluconeogenesis?
The kidney can perform gluconeogenesis during prolonged fasting/starvation.
___ declines over time while ____ increases
Where is the glucose coming from throughout a fast?
-As this is digested glycogen stores are broken down.
-As Glycogen is diminished gluconeogenesis kicks in
-After several days gluconeogenesis slows and ketogenesis increases
What happens in a starved state?
-Increased muscle protein breakdown
-Loss of digestive and nutrient processing enzymes
-Increased AA oxidation
-Increased urea production
-Increased ammonia production