The Relationship Between Serum Leptin Concentration And Body Fat, Gender, Age And Sex Hormones

Background: Obesity has become a serious problem in today's world.Many developed countries are now having more and more obese individuals. Not only obesity affects appearance, it also affects daily life. If it can not be controlled to a better state, it would develop to the state of insulin resistance, hypertension, dyslipidemia, atherosclerosis and so on. For this reason, Obesity and its relating factors have become one researching focus of the modern world. Leptin is a kind of protein hormone secreted by fat cells. It can exert important functions concerning fat metabolism and the control of body weight.Objective: Investigate serum leptin concentrations of normal-weightedand obese Chinese people and assess the relationship between serum leptin concentration and fat mass, gender, age, estrodial and testosterone. Make basic investigations for further understanding of its physiological functions and its effects to human metabolism.Methods: Choose 476 cases from patients and population for physicalexaminations from Tianjin Medical University. Measure their heights, weights, waist and hip circumstance. Test their serum leptin concentrations with IRMA. Test their serum estrodial and testosterone concentrations with RIA. Statisticalanalyses were performed with SPSS 10.0. Results:1. The mean serum concentration of leptin in female subjects is 14.94?8.36ng/mL and its distribution range is 4.27-74.26ng/mL; in male subjects it is 7.58 4.80ng/mL, and its distribution range is0.12-36.92ng/mL.2. After grouping the subjects according to BMI, the mean serum leptin concentration in obese males is 9.52 4.28 ng/mL, in obese females is 17.98 8.99 ng/mL; the mean serum concentration of leptin in normal- weighted males is 3. 65 2.52 ng/mL, in normal- weighted females is 9.61 3.05 ng/mL.3. Dividing the subjects according to gender, BMI and age, the mean serum leptin concentration of every subgroup is different. But the results of the statistical analyses show that their difference does not reach a significant degree.4. In obese male, In(Leptin) has a negative correlation with ln(T)(r = -0.209, P = 0.049); In normal-weighted males, In(Leptin) and ln(T) has a negative correlation that don't reach statistical significance. In normal-weighted females, ln(Leptin) shows a tendency to increase with ln(E2); In obese females, In(Leptin) decreases with the increasment of ln(E2).Conclusion:1. The difference between male and female serum leptin concentration is significant.2. BMI is an important factor to determine serum leptin concentration.3. Age does not have significant effects on serum leptin concentration in adults.4. Testosterone (T) is an important factor to decide serum concentration of leptin in males. While in females, estrodial (E2) does not affect serum leptin concentration to a significant degree.