Regulation of Energy Intake & Body Weight Regulation Flashcards
Role of hypothalamus in regulation of energy balance and body weight regulation
- Hypothalamus involved in both control of short- and long-term regulation of body weight
- PVN, VMN, Arc, LH regulate food intake/disposition
- Process information concerning peripheral energy stores
- Then stimulate or inhibit feeding/alter gastric motility and food metabolism/utilization
Role of ventromedial nucleus (VMN) in regulation of energy balance and body weight
- Inhibitory (-)
- “Satiety center”
- If your ventral (tummy) region is full –> stop eating
- Stimulation of this region results in cessation of eating even in hungry animals
Role of lateral hypothalamus in regulation of energy balance and body weight
- Stimulatory (+)
- Causes voracious eating via melanin-concentrating hormone (MCH) and orexins (hypocretins)
- If your lateral region is skinny, keep eating
Role of arcuate nucleus (Arc) in regulation of energy balance and body weight
- Inhibitory and stimulatory (+/-)
- Activation can produce hunger via NPY/AgRP
- Also can produce satiety via a-MSH/POMC-CART

Mechanisms used by hypothalamus to promote/inhibit food intake
- Regulating food intake (hunger/satiety)
- Altering gastric motility
- Altering food metabolism/utilization
- Neurons in LH support behaviors like chewing, licking, swallowing (via cranial nerves)
Impact of knocking out the POMC gene
- Also knocks out a-MSH
- Increase body weight
Impact of knocking out NPY gene
- Decrease weight
Impact of loss-of-function mutation in melanocortin receptor (MCR)
- Increase weight
Peripheral hormones derived from GI tract (4)
- Ghrelin (stomach)
- CCK (duodenum)
- PYY (distal ileum)
- GLP-1 (distal ileum)
Role of ghrelin in regulating food intake/body weight
- Stimulatory (+)
- Makes your tummy growl, peaks prior to a meal
- Ghrelin = growlin’
- Stimulates NPY/AgRP neurons
- Works opposite to leptin and insulin
- Increases food intake
Role of CCK in regulating food intake/body weight
- Inhibitory (-)
- Senses food
- Activates vagal afferents in peritoneum and area postrema
Role of PYY in regulating food intake/body weight
- Inhibitory (-)
- Anorexic effect via inhibition of hypothalamic NPY/AgRP neurons
- Decreases food intake
Role of GLP-1 in regulating food intake/body weight
- Inhibitory (-)
- Incretin hormone
- Acts on area postrema via NTS
- Reduces food intake
Peripheral hormone released from the pancreas & its role in regulating food intake/body weight
- Insulin! (durrr)
- Inhibitory (-)
- Works like leptin
- Levels parallel body fat content
- Receptors in hypothalamus and brainstem
Peripheral hormone released from adipose tissue & its role in regulating food intake/body weight
- Leptin
- Inhibitory (-)
- “Satiety hormone”
- Receptors in arcuate nucleus and VMN
- Inhibits NPY/AgRP
- Activates a-MSH/CART
- Found by mouse model –> knockouts are hugely obese
- Not the silver bullet of obesity cure
Role of brain reward pathways & environmental cues in development of obesity
- Food is rewarding
- We override homeostatic signals to stop us from eating –> get fat
- Taste info goes through NTS to hypothalamus, thalamus, amygdala, forntal cortex
- Affects areas of feeding & satiety PLUS motivation & reward
- Nucleus accumbens and dopamine afferents involved in drug addiction PLUS induction of feeding
- Serotonin also impacts feeding (phen/fen used as obesity tx)
- SSRI activates a-MSH/CART neurons –> decrease food intake
- Eating is cognitive/executive decision
- Affected by social/environmental cues, depression, anxiety
Internal inputs to food intake behavior
- Reward mechanisms
- Cravings
- Thinking about food (you are now, aren’t you?)
- Restraint - can you ignore a delicious cookie? (nope)
- Learned behaviors - how did you learn to eat?
- Attention
External inputs to food intake behavior
- Environmental cues
- Sight
- Smell
- Taste
- Availability and portions
- Social context
- Time cues
Simplified “cause” of obesity
- Non-homeostatic regulation (internal and external inputs) overrules homeostatic physiologic regulation of energy intake