Obesity

Question 1

Adipocytes

Answer 1

Store TGs
Synthesize fatty acids/TGs from carbohydrates
Break down stored fats
Release fatty acids for energy
Produce hormones – leptin

Question 2

Regulation of hunger

Answer 2

Lateral hypothalamus: stimulation -> hunger, inhibition -> anorexia
-inhibited by leptin

Ventromedial nuclei: stimulated by leptin
Stimulation -> satiety
Lesion -> hyperphagia

Question 3

BMI

Answer 3

Wt kg/(height m2)

Underweight less than 18.5
Normal 18.5-24.9
Overweight 25 – 29.9
Obese over 30

Question 4

Hormonal regulation of fat utilization

Answer 4

Heavy exercise and stress -> mobilization and utilization of fat

Increased sympathetic stimulation -> epi and NE release from adrenal medulla

Epi activates hormone-sensitive TG lipase in fat cells -> rapid breakdown of TG, FAs to muscles as energy

Stress triggers release of ACTH -> glucocorticoids

Cortisol stimulates triglyceride lipases -> more free fatty acids to be used by muscles

Question 5

Lipodystrophy

Answer 5

Abdominal obesity w/ no fat on extremities
Buffalo hump

Cause: leptin deficiency
Protease inhibitors – HIV meds

Question 6

Obesity meds

Answer 6

Atypical antipsychotics
Mirtazapine
Insulin, TZDs, sulfonylureas
Progestins

Question 7

Medical complications of obesity

Answer 7

Metabolic syndrome
T2DM
HTN
Atherosclerotic diseae: CAD, MI, PAD, stroke
OSA
Gout
Gallstones
PCOS
Fatty liver
OA
Candida infections of skin folds

Cancer: esophageal, colon, liver, gallbladder, pancreatic, breast, ovarian, uterine, prostate, NHL, multiple myeloma

Question 8

Nonalcoholic steatohepatitis (NASH)

Answer 8

MC causes: obesity, T2DM, hyperlipidemia, insulin resistance

d/t insulin resistance at liver -> excess lipid accumulation in liver

-> cirrhosis, hepatocellular carcinoma, worsen Hep C progression

suspect if chronically elevated LFTs

Dx:
Liver US, CT scan, MRI
Magnetic resonance spectroscopy (gold standard)
Liver bx