Flashcards in Feast or Famine (5/13) Deck (15)
What does leptin do?
Leptin is secreted by adipose cells and acts in hypothal to suppress feeding, inc energy expenditure and dec body wieght and fat. It works by inhibiting NPY and AGRP and stimulating alpha MSH (which binds MC4R receptor to inhibit food intake)
What is ghrelin
Acts on brain to stim feeding and gastric motility. Feeding inhibits ghrelin
Where does lipid accumulate in obesity? What does it lead to?
Liver, muscle, pancreas leading to a predisposition toward inflammation and organ dysfxn (insulin resistance)
What predisposes to obesity?
The fact that hunger/satiety, fuel homeostasis, metabolic rate, and hormones are controlled by polygenic factors
What single-gene mut can cause obesity?
-Leptin deficiency (leptin gives feedback inhibition to brain to supp feeding and inc energy expenditure)-->reversed via leptin injections
-Loss of MC4R (binds alpha-MSH, a factor stimulated by leptin that inhibits food intake)
How do we know environmental factors must play a role in obesity?
Obesity rates have inc 3x worldwide from 1980-2008
What environmental factors have contributed to inc in obesity?
-Ave caloric intake inc
-Food portions inc
-Energy density inc (cal/g)
Who is more at risk for diabetes, sleep apnea, CVD and cancer?
Ppl with high BMI, abdnominal fat, depostiion, sarcopenia (loss of muscle), inc age
What is steatosis
Fat storage in other tissues, result of obesity
What are the consequences of steatosis?
Inc oxidative stress, mitochondrial dysfxn and ER stress in the cell which can inhibit insulin signaling, cause inlammation
How does orlistat work vs other wt loss drugs?
Orlistat blocks abs of dietary fat, all others are aneorexants
What are the 3 kinds of bariatric surgery?
-Adjustable gastric banding
-Vertical sleeve gasteectomy (remove 40% of stomach)
-Roux en Y gastric bypass: surgery shunts food directly from stomach to lower intestine (most effective)
What is cachexia?
WAsting syndrome resulting from cancer and chronic diseases
How are anorexia and cachexia different?
Inflammatory cytokines are seen in cachexia, but not other states, similar to chronic inflammation