14) Obesity & endocrine control of food intake Flashcards
What does the hypothalamus balance?
food intake + energy expenditure
Which part of the hypothalamus in particular is involved in regulation of food intake?
Arcuate nucleus
What is special about the arcuate nucleus?
Circumventricular organ-incomplete BBB (allows peripheral hormones access)
What are the 2 neuronal populations in the arcuate nucleus and what do they do to appetite?
NPY/argp-increases appetite
POMC/alpha MSH-decreases appetite
Are the mutations in the NPY or POMC nuclei?
No mutations in NPY
POMC deficiency/MC4 receptor mutations–>obesity
What is leptin made up of?
167 aa’s
What does leptin do and activate?
Leptin tells your body you’re not starving/how much body fat you have
-stimulates POMC neurones
Where is leptin stored?
Adipose tissue
When are leptin levels high and low?
High=high body fat
Low=low body fat
What happens regarding leptin during obesity?
Leptin resistance
What does an absence of leptin cause and lead to?
Obesity
- POMC not activated=appetite not decreased
- hyperphagia
- infertility
- no puberty
So obesity causes….
and absence of leptin causes……
obesity–>leptin resistance
absence of leptin–>obesity
Why can athletes get hypothalamic amenorrhoea?
such low body fat=low leptin
Which 2 chemicals are proportional to body fat?
Leptin
Insulin
What does insulin do peripherally vs centrally?
Peripherally=lowers BGC
Centrally=reduces food intake
