cardiac metabolism Flashcards
how many kg of ATP does heart use per day, and what is the % thru different kinds of metabolism
6 kg
95% thru oxidative metabolism
5% thru non-oxidative metabolism via glycolysis
5 metabolic fuels used by the heart, and % ATP generated by top 3
fatty acids (40-60%)
glucose (20-40%)
ketone bodies (10-15%)
lactate
branched chain AAs
FA metabolism in cardiac cell mechanism
FA uptake by CD36 or FAT
->
converted to fatty-acyl CoA by ACSL1
->
to TAG synthesis for storage
OR
to mitochondria via CPT1
what can CPT1 be inhibited by
malonyl-CoA
what 2 things can lead to CPT1 no longer being inhibited
increased AMP
increased AMPK
what does the Randle Cycle show
how there’s competition between FA beta-oxidation and glucose/lactate oxidation
->
bc they both produce acetyl-CoA
what does acetyl-CoA activate and what does it inhibit
activates PDH kinase
inhibits PDH
increased acetyl-CoA = _____ pyruvate = _____ glucose/lactate oxidation
decreased pyruvate
decreased glucose/lactate oxidation
increased acetyl-CoA = _____ citrate = inhibits _____
increased citrate
inhibits PFK-1 (glycolysis)
neonatal / fetal heart (vs adult heart) has what 4 things
less O2
more glucose use
GLUT1 primary glucose transporter
heart can regenerate
when are ketone bodies used in cardiac muscle
fasting, hypertrophy
when are BCAAs (amino acids) used in cardiac muscle
starvation
mechanism of ketone body use in cardiac muscle
uptake by SLC16A transporter
what are BCAAs used for in cardiac muscle
for ATP production
function of creatine phosphate in cardiac muscle
a spacial buffer that stores high energy bond of ATP
shuttles ATP from mitochondria to other locations in the cell that need it
reaction that produces creatine phosphate
creatine + ATP <–(creatine kinase)–> ADP + creatine phosphate
how disturbed cardiac metabolism causes an MI
increased glycolysis
->
increased lactate production
->
lactate accumulation
->
pH drops (disrupts ion gradient across sarcolemma)
->
a lot of ATP used to repair gradients
->
less ATP for contraction
->
heart injury
cardiac-specific markers of injury
CK-MB
troponin (gold standard)
markers of injury not specific to cardiac muscle
CK
LDH
myoglobin
