Lecture 24-Endocrinology of Obesity

Question 1

which hormones are responsible for:

• satiety signaling
• glucostatic signaling
• lipostatic signaling

Answer 1

• satiety: CCK, GLP-1 (anorexigenic), ghrelin (orexigenic)
• glucostatic: insulin, glucagon, Epi
• lipostatic: leptin (upregulates UCP in brown fat, lipolysis in white fat)

Question 2

Which fat growth factors play a role in preadipocyte differentiation? Which ones promote insulin resistance? (6)

Answer 2

• visfatin
• adiponectin
• leptin
  Insulin resistance inducing:
• TNF-alph
• IL-6
• resistin

Question 3

Which fat-secreted hormones play a role in improving one’s state of insulin resistance? (3)

Answer 3

• leptin
• adiponectin
• visfatin (PBEF)

Question 4

Which fat-secreted hormones play a role in declining one’s state of insulin resistance? (6)

Answer 4

• TNF-alpha
• IL-6
• resistin
• MCP-1
• angiotensinogen
• PAI-1

Question 5

NHANES

Answer 5

• correlated cardiovascular risk factors/metabolic abnormalities with obesity. Took into account bp, TAGs, fasting blood glu, C-reactive protein
• presented idea of healthy obese: insulin-sensitive population with better cardiovascular risk factors than normal weight people (fasting glu, fasting insulin, insulin clearance rate, 2 hr PP glu)
• 1/3 of normal weight ppl had metabolic abnormalities
• 1/3 of obese did not have metabolic abnormalities
• 50/50 with overweight people

Question 6

Other than playing a role in weight gain and satiety, what other roles does leptin play? (4)

Answer 6

• fertility: helps in development of female reproductive tract and onset of puberty. There’s a leptin surge right before male onset of puberty
• immune function
• energy expenditure
• body temperature

Question 7

How does leptin alter neural connections in the brain with regard to hunger?

Answer 7

In ob/ob mice, the absence of leptin has caused upregulation of excitatory inputs and down regulation of inhibitory inputs into NPY/AGRP neurons
- has down regulated excitatory inputs to POMC neurons

Question 8

How does adenovirus 36 affect one’s weight and how?

Answer 8

• causes weight gain and potentially obesity
• may cause decrease in leptin secretion
• causes upregulation of viral enzyme E4orf1 which increases lipogenic enzymes that promote TAG storage and differentiation of stem cells into adipocytes