Endo 15: Endocrine control of food intake Flashcards
What is the input to the hypothalamus
GHRELIN, PYY & other gut hormones
Neural input from the periphery and other brain regions
LEPTIN
What are the outputs of hypothalamus
Food Intake
and
Energy Expenditure (TRH)
Why is paraventricular nucleus important
Releases TRH
Where is arcuate
Bottom of hypothalamus next to the 3V
How does arcuate receive hormonal input. What function does arcuate nucleus serve
Incomplete blood brain barrier, allows access to peripheral hormones.
(circumventricular)
Integrates peripheral and central feeding signals.
What are the key neuronal populations in the arcuate nucleus
Stimulatory (NPY/Agrp neuron)
Inhibitory (POMC neuron)
How is POMC used in different brain areas
pituitary cut up to ACTH
Hypothalamus cut up to MSH
What hormone is present in the paraventricular nucleus and the function
MC4R…. reduces appetite
How does POMC neuronal bodies affect paraventricular nucleus
Releases a-MSH to stimulate PVN to decrease food intake
How to AGRP/NPY affect PVN
releases AGRP which inhibits MCR4 so increased appetite
T/F NPY and Agrp mutatuons are responsible for obesity prevalence
F!! POMC deficiency and MC4-R mutations cause morbid obesity, but NOT responsle for obesity prevalence
What does the hypothalamus receive signal from
From leptin, the gut and brainstem as well as cortical regions
What is the ob gene, what occurs in deficiency
Ob gene codes for leptin in ob/ob mouse there is no leptin, nothing to tell the brain that there are adequate fat stores in the adipose tissue
Profoundly obese. Hyperphagia. Diabetic. Decreased body temperature. Decreased energy expenditure.
What is leptin, where is it released, and where are its receptors
Leptin released from WHITE adipose tissue
Leptin receptors in the hypothalamus (Ob-R)
How does leptin work on the hypothalamus
Activates POMC and inhibits NPY/AgRP neurons.