Obesity

Question 1

Notes on leptin

Answer 1

• Produced in adipocyte
• Levels related to fat/adipocyte mass
• Acts on receptors at the hypothalamus to produce satiety → when patients reach a certain peripheral fat mass, leptin acts as a lipostat
• Leptin resistance can be seen in obesity → patients continue to gain weight and addition of leptin does not help to curb weight gain
• Functions to inhibit food intake (reduces the expression of neurotransmitters that stimulate intake - neuropeptide Y and agouti-related peptide) and increase energy expenditure

Question 2

Pregnancy complications of obesity

Answer 2

• Gestational hypertension
• Pre-eclampsia
• Gestational diabetes
• Preterm premature rupture of membranes
• Preterm delivery
• Fetal Macrosomia (Birthweight >4000g)
• Placenta previa
• Placental abruption
• Operative vaginal delivery

Question 3

Notes on adiponectin

Answer 3

• Levels inversely related to body fat
• Levels increase with
  
  • Exercise
  • Low calorie diet induced weight loss
  • Weight loss following bariatric surgery
  • Thiazolidineone therapy
• Levels decrease with
  
  • Obesity
  • Diabetes

Question 4

Which genetic mutation is the most common monogenetic cause for obesity

Answer 4

• MC4-R mutation

Question 5

Hormones that stimulate appetite

Answer 5

1. Ghrelin from stomach (ghrelin makes stomach growl)
2. Neuropeptide Y (from hypothalamus)
3. Agouti-related peptide (from hypothalamus)

Question 6

Hormones that inhibit appetite

Answer 6

• Gut
  
  • Pancreatic polypeptide
  • Oxyntomodulin
  • Peptide YY
  • Cholecystokinin
  • GLP 1
• Adipose tissue
  
  • Leptin
  • Insulin
• Hypothalamus
  
  • Cocaine and methamphetamine regulated transcript
  • Alpha melanocyte stimulating hormone

Question 7

Notes on ghrelin

Answer 7

• Peptide hormone secreted from stomach
• Increases preprandially and timulates appetite
• Higher levels found in leaner subjects
• Increased levels in Prader-Willi syndrome
• Reduced levels post gastric bypass surgery

Question 8

What is the most effective treatment for morbid obesity

Answer 8

• Bariatric surgery (20-30% weight loss in patients with BMI>35)
• More effective than non-surgical interventions
• Reductions in BMI influenced by type of surgery - greater following combination procedures rather than purely restrictive procedures