Regulation of Metabolism Flashcards
the 3 priorities (in order) for fuel utilizat
- maintain stable supply of substrates for the CNS and its functions….the brain has little ability to store energy.
- in the well fed state = prefer glucose
- in fasting state = can use ketone bodies - maintain protein reserves
- fasting state = metabolic pathways minimize utilization of proteins, and protein reserves are not regenerated either
- well fed state = protein reserves will be replenished before glycogen reserves - replenish the limited reserves of glycogen in both liver and muscle tissues
well fed state (general)
a. blood glucose levels are good enough for brain supply
b. glycogen is made and stored in muscle and liver cells (but not brain and fat cells)
c. fat is stored in adipose cells primarily
d. high insulin:glucagon ratio –> signals the body to make proteins, store glycogen, and store fat
fasting state (general)
a. glucose is moved from the glycogen stores
b. gluconeogenesis will be active
c. fat stores will be tapped –> moving TGs for energy
d. protein stores can be used
excitement state (general)
= adrenaline (epinephrine) rush –> catecholamine produced from phenylalanine and tyrosine in the adrenal gland
promotes rapid elevation of blood glucose levels and mobilization of fat stores
beta cells of the pancreatic islets
cells that produce insulin
which amino acid promotes insulin secretion
arginine
most potent stimulator of insulin secretion
high blood glucose
gastric hormones that promote insulin secretion
gastric inhibitory polypeptide
CCK
**these hormones are made after a meal - so can stimulate insulin secretion in anticipation of rising blood glucose levels
GLUT4
transporters that facilitate glucose entry into cells under high insulin levels
insulin effects (general)
- glucose uptake into cells (GLUT4)
- uptake of branched chain amino acids (Val, Leu, Iso)
- inhibition of protein degradation
- (+) glycogen synthesis (glycogen synthase)
- (-) gluconeogenesis
insulin and glucokinase (liver)
(+) glucokinase expression
increase liver uptake of glucose
glycogen phosphorylase and insulin
(-) activity
glycogen breakdown - which is not needed in a well fed state
glycolysis under high insulin
increased glycolysis (less gluconeogenesis at the same time)
(+) PFK-1 (via + PFK-2)
(+) pyruvate dehydrogenase complex
result = increase AcCoA production in liver and muscle
FA synthesis under high insulin
increased (liver)
(+) AcCoA carboxylase
TG synthesis under high insulin
increased (adipose tissue)
(+) lipoprotein lipase
pancreatic alpha cells
make glucagon