TOPIC A/3: Fed and starving states Flashcards
What fuels does the brain use
predominantly uses glucose, fatty acids cannot cross BBB
in starvation relies on ketone bodies
ideal blood glucose level
~4.5 mM (60−90 mg/dL)
when is insulin usually secreted
after a meal as blood glucose is high
when is epinephrine released
periods of immediate stress or activity to stimulate energy mobilisation
predominantly targets muscles
Outline fed state
<4 hours after meal
lipogenic liver favours storage of energy and fat
exogenous fuels
insulin increase
glycogenesis
Outline fasting state
> 4 hours after meal
glucogenic liver
glucagon increase
glycogenolysis and gluconeogenesis
TAG hydrolysis
Outline prolonged fasting/starvation state
days after a meal
muscle break down
liver deaminates amino acids
carbon skeletons produce glucose and ketone bodies for brain and body fuel
last resort: protein breakdown to produce glucose while ketone body store is being built up.
outline ketone body production from fatty acids
normally fatty acids enter beta oxidation but producing Acetyl-CoA for CAC is not net gain due to oxloacetate
ketone bodies produced instead
what are the 3 main ketone bodies
Acetone
Acetoacetate
beta-hydroxybutyrate
last 2 dangerously lower blood pH
Outline type 1 diabetes mellitus
juvenile diabetes / insulin dependent (IDDM)
immune system destroys beta cells in pancreas
no insulin produced
no signalling for present mobile energy
CV and renal disease
Outline Type 2 diabetes
adult onset / non insulin dependent (NIDDM)
resistance to insulin signal
lipid burden hypothesis: adipocytes too packed, increased FA in blood which enter muscle and liver. lipid droplets cause loss of sensitivity to insulin
Implications of diabetes
hyperglycaemia
breakdown of muscle and protein
increased urination and dehydration
glycosylated proteins like haemoglobin compromises O2 delivery
treatment of diabetes
type 1: insulin
type 2: maybe insulin, proper dieting
