Lecture 6: Obesity 1

Question 1

Statistics

Answer 1

61% of adults in the US are overweight or obese
Approximately 300,000 deaths each year attributable to obesity
Obesity subtracts 6 years from life expectancy

Question 2

Causes

Answer 2

Polygenic
Ex. Leptin deficiency, Prader Willi- imprinting of chromosome 15 causes children to continuously eat
Non-genetic cause- Stroke to the hypothalmus
Non-Genetic Environment- Socioeconomic class, smoking cessation, food activity, drugs, endocrine disorders
Fat is biologically active
Genetics do not point to a single problem
Appetite control is much more complicated than previously argued

Question 3

Health implications of obesity

Answer 3

Type II Diabetes
High Blood pressure- hypertension
High blood cholesterol
Insulin resistance and glucose intolerance
Stroke
Depression
Gout
Coronary Heart Disease

Question 4

Adipose Tissue

Answer 4

Responsible for regulating the triacylglycerol cycle which circulates fatty acids and triacylglycerols between adipose and liver
Two Components:
Systemic Component- Recycles Fatty acids released from adipose tissue
Intracellular Component- Recycles fatty acids that enter the adipocytesfollowing tracylglycerol hydrolysis

Question 5

Types of Adipose Tissue

Answer 5

Brown Fat- Enriched with mitochondria, less with triglycerides
White Fat- Rich in triglycerides, also synthesizes adipokines
Generates heat- allows for protons to run back along the inner mitochondrial membrane without producing ATP- energy is instead released as heat

Question 6

Adipocytes Secreted Protein

Answer 6

Pro-Hyperglycemic: Resistin, RBP4

Anti-Hyperglycemic: Leptin, Adiponectin, Visfatin, Omentin

Question 7

Leptin

Answer 7

Discovered through mouse experiment
OB does not produce leptin, does not sense leptin
Encodes for satiety

Question 8

Genetics of Obesity

Answer 8

50%-90% variation
Complex polygenic disorder
20 monogenic obesity disorders- rare

Question 9

Thrifty Gene Hypothesis

Answer 9

Thrifty genes enabled our human predecessors to store energy from plentiful times to survive during famine

Question 10

Drifty Gene Hypothesis

Answer 10

Genetic drift to obesity following the removal of predators

Question 11

Epigenetics

Answer 11

Nutrition in early life determines DNA methylation and histone acetylation
Study showed children born after surgical weight loss surgery had a better metabolism

Question 12

Stomach Hormones

Answer 12

Ghrelin- Hunger, GH release

Gastrin- Acid Secretion

Question 13

Pancreas Hormones

Answer 13

Insulin- Glucose homeostasis
Glucagon- Glucose homeostasis
Pancreatic Polypeptide- Satiation
Amylin- Glucose homeostasis

Question 14

Intestine Hormone

Answer 14

Oxyntomodulin- Satiation
PYY- Satiation
GLP-1- Satiation

Question 15

Brain Regulation Hypothalamus

Answer 15

Receives signals from
GI tract, nutrients in blood, Adipocyte hormones, and cerebral cortext( sight smell)
Contains hunger and satiety centers: chemical cross talk among neurons to coordinate feeding behavior