| Summary: | 博士 === 國立臺灣師範大學 === 體育研究所 === 89 === Leptin is exclusively secreted by adipose tissue. Rodent studies have demonstrated that leptin can affect thermogenesis, increase physical activity, inhibit appetite and decrease body fat. In humans, circulating leptin levels correlate closely with body fat content. Purpose: This study examined the differences in the distribution of abdominal fat among three groups of individuals who engaged in long-term regular exercise (runners, R; swimmers, S; and weight lifters, W; 12 males in each group) and a sedentary group (control, C; 12males). The relationships between abdominal fat distribution, fasting leptin, insulin and testosterone were also studied. Results: There were no significant differences among the four groups in % body fat. (R:9.26 + 2.93，S:12.39 + 2.43，W:9.74 + 4.15，C:11.36 + 3.36%). Also the total abdominal fat volume and abdominal subcutaneous fat volume were not different among groups. However, the visceral fat volume in the R group was significantly lower than the C and S groups (mean + SD, R = 0.40 + 0.27; S = 0.95 + 0.46; W = 0.66 + 0.26; C = 0.85 + 0.33 L, P < 0.05). Fasting serum leptin, insulin, and testosterone did not differ significantly among groups (leptin, R: 1.64 + 0.62, S: 2.51 + 0.73, W: 2.38 + 1.76, C: 2.30 + 1.80 µg/L; insulin, R: 13.51+ 5.17, S: 17.15 + 4.42, W: 17.22 + 12.93, C: 15.45+ 6.13 ng/ml: testosterone, R: 7.05+ 1.63, S: 5.58 + 1.41, W: 6.06+ 1.13, C: 6.16+ 2.34 ng/ml). But leptin was significantly correlated with abdominal total adipose tissue volume and abdominal subcutaneous fat volume for all 4 groups. When the ratio of abdominal visceral fat volume (AVFV) to total abdominal fat volume (TAFV) was smaller (R:0.18, W:0.21), leptin and AVFV were significantly correlated (R = 0.89, W = 0.72, P < 0.05)；when the ratio of AVFV to TAFV was larger (S:0.26, C:0.28), leptin and AVFV were not correlated. No significant relationship between leptin and insulin, leptin and testosterone was observed in R, S and W groups. Conclusions: Long-term regular exercise can help to maintain and decrease body fat. Long-term runners have the lowest visceral fat volume. Based on the relationship between leptin and abdominal fat volume distribution, adipose tissue volume is an important factor for correlation with leptin. Further research is needed in order to understand difference between long-term exercisers and sedentary individuals in concerning the ratio of AVFV to TAFV change and leptin.
|
|---|
