In the hypothalamus there are 2 centers:
Feeding Center Stimulation evokes feeding behavior-Destruction induces anorexia and
Satiety Center Stimulation causes cessation of eating-Destruction causes hyperphagia and obesity activity of satiety center may be regulated by glucose utilization of cells within the center which would serve as Glucostat
Neurotransmitters include:
1) Catecholamines
2) Neuropeptide Y
3) Amphetamine
Other factors influencing appetite:
Gastrointestinal hormones: CHOLECYSTOKININ
Stimulatory substances from fat depots e.g. Adipsin
Genetic component
It is synthesized in adipocytes under control of the obese (ob) gene
Mice that lack the ob gene become obese
however: obese humans have high blood levels of leptin
therefore, human target tissues may not be responsive to leptin
CHOLECYSTOKININ (CCK)
is a peptide secreted by cells of small intestine, neurons in brain and gut
it stimulates secretion of pancreatic enzymes and gallbladder secretion
Acts as a satiety signal and decreases appetite both through peripheral and central pathways
ADIPSIN (lipostat theory)
is a protein secreted by the adipocytes, inhibits triglyceride synthesis, and is deficient in genetically obese rodents
Lack or loss of appetite for food
individual takes little food and becomes greatly emaciated
BULIMIA
(FROM LATIN BOUS, OX AND GREEK, LIMOS, HUNGER)
Abnormal increases in the sensation of hunger or Hyperorexia, individuals satisfied only with large meals (different from polyphagia)
OBESITY
Increase in body weight beyond skeletal and physical requirements resulting from excessive
accumulation of fat
alimentary
endogenous
exogenous
hypogonadal
hypothyroid
role of brown fat?
others
Anorexia nervosa and bulimia are associated with:
Growth retardation and impairment
Retardation of onset of puberty
Amenorrhea (Lack of menses)
Hormonal disorders
Psychiatric and neurologic alterations
Others