Regulation of Energy Flashcards
Arcuate nucleus
contains first order neurons that promote either food intake (NPY/AgRP) or satiety (POMC/CART)
POMC gives rise to alpha-MSH
Paraventricular Nucleus
Innervated by arcuate nucleus neurons
House MCR - melanacortin receptors
House NPYR - Neuropeptide Y receptor
Lateral Hypothalamus
Hunger center - expresses MCH and orexins - eating
Ventromedial Nucleus
Satiety center
Knock out of POMC gene?
This will fuck with alpha-melanocyte stimulating hormone
Alpha-MSH lowers intake and increases expenditure –> so getting rid of it will lead to weight gain
Knock out of NPY gene?
Neuropeptide Y is a hunger hormone - increases intake and decreases expenditure –> knocking out will lead to weight loss
Loss of function in MCR
If melanocortin receptor cannot be stimulated, and its stimulation leads to decreased intake and increased expenditure - then we will have weight gain
Grehlin
peptide hormone secreted from stomach that induces feeding
Receptors in arcuate nucleus - food intake
Activates NPYR/AgRP neurons
Stimulats anabolic pathway
CCK
Released from duodenum in response to food - stimulates POMC/CART pathway –> alpha-MSH –> decreased intake / increased expenditure
PYY
Released from L cells in distal ileum - acts by INHIBITING NPY/AgRP neurons
Inhibits anabolic pathway
GLP-1
Released from ileum - reduces food intake
Inhibits anabolic pathway
Insulin
Levels correlate with body fat content -
Stimulates POMC/CART
Inhibits NPY/AgRP
Leptin
Released from fat- more fat - more leptin
activates POMC/CART - catabolic
inhibits NPY/AgRP - anabolic
Leptin in obesity?
Obese prone have much higher leptin but don’t seem to have lower hunger - leptin resistant?
Grehlin in OP vs OR
Slightly higher in OR
PYY in OP vs OR
Slightly higher in OR
Non-homeostatic regulation of energy intake
Internal Reward/craving/thought/restraint/attention/ learned behaviors External Environment - sight/smell/taste availability social time cues
When hungry
Hedonic foods compared to basic objects
fMRI we see
increased: attention reward motivation memory especially in fluffly
Obese resistant vs obese prone brain activity pre and post meal?
OR have slightly higher signals pre-feed that remit post-feed
OP signals don’t remit post-feed
As we saw fMRI brain reward/motivation/attention signals in obese prone do not remit post-feed
WHAT can help?
EXERCISE :)
Homeostatic regulation
Adiposity
Metabolites
Gut Peptides
Gastric distension
All talk to the hypothalamus
Non homeostatic regulation
Internal and external cues
also talk to the hypothalamus
Prof thinks overrides hypothalamus in obesity
Elevated levels of grehlin would do what to NPY and alpha-MSH
NPY is hunger so these would rise
Alpha-MSH is satiety so these would fall
