feast or famine Flashcards
What does acetyl-CoA inhibit and activate?
inhibit = pyruvate dehydrogenase
activate = pyruvate carboxylase
What does AMP signal?
low energy charge
What does AMP activate regarding sugar metabolsim?
AMP activates glycogen phosphorylase and PFK1
What does citrate regulate regarding fat and sugar metabolsim?
citrate activates acetyl-CoA carboxylase
citrate inhibits PFK1 and PFK2
Regarding sugar metabolism, what does F16bP activate?
pyruvate kinase
What does malonyl-CoA inhibit?
CPT-I
cAMP induces gluconeogenesis and inhibits lipid synthesis via what?
CREB
Can fatty acids cross the blood brain barrier?
no
Can fatty acids be converted to glucose?
NO
How do RBCs provide energy?
glycolysis
What do muscles prefer for their energy needs?
fatty acids
Other than fats, what else can muscles use for their enery requirements?
glucose and ketone bodies
What does the heart prefer for an energy source?
fatty acids
What does the brain use for energy?
exclusively glucose
During the well-fed state, where is glucose stored?
muscle and liver
During the well-fed state, what does the liver convert excess glucose into?
VLDLs
What are amino acids used for in the well-fed state?
protein synthesis.
Excess AA’s are converted into glucose or ketone bodies
During the early fast, what happens to glucose stores?
glycogen stores are released as glucose
During the early fast, what happens to fatty acids and glycerol stores?
released from adipose tissue
During the early fast, what does the liver produce regarding fats?
ketone bodies
During the early fast, what happens to muscles?
amino acids are released from muscles
During the early fast, what does the liver do to amino acids?
converts them to glucose and ketone bodies
When do enzymes of the urea cycle get turned on?
during the early fast
What signals the late starvation?
release of corticosteroids
In the late fast, what does the brain begin to use for an energy source?
ketone bodies
What other organ, excluding the liver, can produce ketone bodies?
Kidney
What sort of enzyme becomes depleted during the late fast?
digestive enzymes
Patient cannot breakdown dietary fats or carbohydrates
Can muscles perform glugoneogenesis?
No
Is lactate produced by the heart?
No
What two stores of energy does the brain not have?
glycogen or fat
When are urea cycle enzymes turned on? Why is this?
the early fast
to cope with increased amino acid breakdown
Regarding metabolism, what do corticosteroids signal?
metabolic rate drops and tissues consume less energy
What does insulin do to potassium and phosphate levels?
insulin moves potassium and phosphate into the cells
During the early fast, which nutrient is utilized first, glycogen or fat?
glycogen
When is the urea cycled induced? Why?
early fast
to cope with the release of amino acids
What two nutrient stores does starvation deplete?
phosphate and potassium
