Fuel Supply Regulation Flashcards
(50 cards)
nutrient depletion sensors (2)
- AMP kinase
- sirtuins
adequate nutrient availability sensor
mTOR system
Cellular stress and excess nutrient sensor
UPR system
Central integrator of nutrient balance location
medial-basal hypothalamus
Signals that indicate adequate nutrient stores (4)
- leptin
- CCK
- GLP-1
- serotonin
Signals that indicate nutrient depletion (2)
- Ghrelin
- Neuropeptide Y
alpha MSH neuronal pathways importance
regulation of hypothalamic output –neuronal and endocrine–ensures energy balance
The regulation of food intake is not adequate to ensure energy homeostasis. What fine-tunes the energy homesotatic balance? How?
Energy–alters the efficiency of fuel and ATP use!
The efficacy of the hypothalamic energy homeostatic control system can be overridden by what type of pathways?
cortical (especially limbic)
-many are related to the function of the dopaminergic reward system
What do AMP kinases sense?
inadequate intracellular energy stores, sensing the intracellular AMP/ATP ratio
When activates, the AMP kinases promote
catabolic pathways
Sirtuin system are what type of proteins? What is their function?
deacetylases, regulating protein function and synthesis in response to intracellular energy stores
When activates, the mTOR complex initiates types of reactions that lead to what?
cellular growth and proliferation
What does the mTOR complex inhibit?
Autophagy
What inhibits the mTOR complex?
Activated AMP kinase
mTOR complexes are an intermediate step in ______
signal transduction for growth factors
AMP kinase indirectly stimulates ___ by inhibiting mTORc
autophagy
What causes unfolded proteins and thus the unfolded protein response? (UPR)
excessive intracellular stores result in synthesis of underglycosylated proteins; undergo inappropriate folding
The UPR process includes
- protein synthesis reduction
- additional protein glycosylation
- synthesis of chaperones
- targets defective proteins toward the proteasomal pathway
One consequence of UPR
increased lipid synthesis and build up of intracellular TGs
Besides intracellular glucose and fatty acids, what other events can trigger UPR?
Hypoxia, increased ROS, viral infection, etc.
In terms of energy homeostasis what determines the size of the energy reservoir?
- caloric intake
- efficiency of calorie digestion and absorption
- caloric usage
CNS centers that sense and modulate the size of the energy reservoir. What do they do? Which is the most important feeding/satiety center?
- dorsal brainstem “feeding center” – NTS, vagal motor nucleus–initiation of feeding programs in response to signals from GI tract and optimize digestion and absorption
- parabrachial nucleus –important in aversion training
- amygdala–taste inputs, feeling of satisfaction and reward, drive for feeding behavior
-hypothalamus is the most important feeding/satiety center
Principal integrator for all the sensory info regarding the status of energy reservoir and coordinates appropriate output signals to maintain optimal energy reservoir size
hypothalamus
