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Leptin and obesity

Leptin and obesity. 指導：周淑娥教授、洪偉珊助教 組員： 57 陳昱愷、 60 陳重宇. Obesity. When people take in excessive energy-rich molecules, they are converted to storage molecules. Order of storage: liver, muscle (glycogen) →adipose cells (fat) Order of expenditure ： liver → muscle, adipose cells .

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Leptin and obesity

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  1. Leptin and obesity 指導：周淑娥教授、洪偉珊助教 組員：57陳昱愷、60陳重宇

  2. Obesity • When people take in excessive energy-rich molecules, they are converted to storage molecules. • Order of storage: liver, muscle (glycogen) →adipose cells (fat) • Order of expenditure：liver → muscle, adipose cells adipose cells nucleus Oil drops

  3. Diseases • Obesity contributes to a number of healthy problems, including the common type of diabetes, cancer of colon and breast, and cardiovascular disease.

  4. D.Coleman’s experiment • In 1973, scientists discovered that mice with mutant ob gene or db gene eat voraciously and grow much more than normal mice. • To explore the roles of genes, Coleman • surgically linked mice’s circulatory systems.

  5. Result • In 1995, Jeffrey M. Friedman discover leptin and its role in regulating body weight. • ob-deficient mice are injected with leptin and lose 30% weight. ob-deficient mice do not produce leptin. • db-deficient mice are injected with leptin and have no change. db-deficient mice do not produce the receptor for leptin.

  6. Leptin • Leptin (Greek leptos meaning thin) plays a key role in regulating energy intake and energy expenditure, including appetite and metabolism. • The gene is located on chromosome 7 in humans. • It is manufactured primarily in the adipocytes of white adipose tissue, and the level of circulating leptin is directly proportional to the total amount of fat in the body. • 由白色脂肪細胞所製造，作用至下視丘 • 刺激生熱效應(thermogenesis)、胰島素敏感性、脂肪酸氧化作用，且降低食慾。 • 體內的脂肪越多，產生的Leptin就越多，來抑制食慾，讓體重回到原來的體重。

  7. function • Leptin acts on receptors in the hypothalamus • counteracting the effects of neuropeptide Y • (2) counteracting the effects of anandamid • (3) promoting the synthesis of α-MSH, an appetite suppressant. • This inhibition is long-term. • The absence of leptin (or its receptor) leads to • uncontrolled food intake and resulting obesity.

  8. Leptin resistance and obesity • In general, obese people have an unusually high circulating concentration of leptin. • These people are said to be resistant to the effects of leptin, in much the same way that people with type 2 diabetes are resistant to the effects of insulin. Fructose and leptin resistance • A study suggests that the consumption of high amounts of fructose causes leptin resistance and elevated triglycerides in rats.

  9. Conclusion • As of today, there are at least five genes and ten kinds of hormones associated with the regulation of body weight. • Reducing the intake of calorie and increasing the consumption of calorie is still the only feasible way to lose weight.

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