血清脂联素浓度与体脂分布及葡萄糖钳夹试验中胰岛素敏感性的关系

目的探讨血清脂联素浓度与体脂分布及组织胰岛素敏感性的关系。方法对44例上海地区正常糖耐量中国人,其中正常体重组(体重指数<25kg/m2)12例、超重组(25kg/m2≤体重指数<30kg/m2)19例及肥胖组(体重指数≥30kg/m2)13例进行扩展高胰岛素正葡萄糖钳夹试验,以钳夹稳态期的胰岛素介导的葡萄糖利用率(Rd)来判定周围组织的胰岛素敏感性。同时测定总体脂[体重指数、体脂百分比(FAT%)、身体脂肪块重量(FM)]、局部体脂[腰围、臀围、腰臀比、腹部皮下脂肪面积(SA)、腹腔内脂肪面积(VA)和股部皮下脂肪面积(FA)],并应用放射免疫法测定空腹血清脂联素浓度。结果(1)在校正年龄、性别后,超重组及肥胖组的血清脂联素浓度(8.7mg/L±4.8mg/L及6.7mg/L±0.8mg/L)均低于正常体重组(15.7mg/L±1.8mg/L,均P<0.01);(2)血清脂联素浓度与体重指数、腰围、腰臀比、FAT%、FM、VA均呈负相关,但与腰围、VA的相关性最强(r值分别为-0.46和-0.53,均P<0.01);(3)血清脂联素浓度与Rd(r=0.52,P<0.01)及糖原合成率(r=0.36,P<0.05)呈正相关,而与游离脂肪酸浓度呈负相关(r=-0.41,P<0.05);(4)多元逐步回归分析表明,血清脂联素浓度是除性别、体重指数、腰臀比或VA、SA以外,对Rd的独立影响因素,其贡献值分别为3.52%和4.84%(均P<0.05)。结论(1)血清脂联素浓度降低与总体脂增加,尤其是腹腔内体脂增加关系最为密切;(2)血清脂联素浓度是独立于体脂因素之外的影响胰岛素敏感性的因素之一。

Serum adiponectin concentration in relation to body fat distribution and tissue insulin sensitivity in the glucose clamp study

OBJECTIVE: To study serum adiponectin level in relation to body fat distribution and tissue insulin sensitivity by using the extended hyperinsulinemic euglycemic clamp technique. METHODS: Extended hyperinsulinemic euglycemic clamp was performed in 44 Chinese individuals with normal glucose tolerance from Shanghai area, including 12 subjects with normal weight [body mass index (BMI) < 25 kg/m(2)], 19 with overweight (25 kg/m(2) < or = BMI < 30 kg/m(2)), and 13 with obesity (BMI > or = 30 kg/m(2)). The rate of insulin-mediated glucose disposal (Rd) during the steady state of glucose clamp was used to assess the peripheral tissue insulin sensitivity. Total body fat depots [BMI, percentage of body fat (FAT%), and body fat mass (FM)], regional body fat depots [waist circumference (W), hip circumference (H), W and H ratio (WHR), abdominal subcutaneous fat area (SA), intra-abdominal fat area (VA), and femoral subcutaneous fat area (FA)] were measured on all subjects. Fasting serum adiponectin level was determined by radioimmunoassay. RESULTS: (1) After the adjustment for age and sex, the serum adiponectin concentrations in the overweight and obesity groups were (8.7 +/- 4.8) mg/L and (6.7 +/- 0.8) mg/L, both significantly lower than that in the normal weight group [(15.7 +/- 1.8) mg/L, both P < 0.01]. (2) Serum adiponectin concentration was negatively correlated with BMI, W, WHR, FAT%, FM and VA, especially with W and VA (r = -0.46, P < 0.01, and r = -0.53, P < 0.01). (3) Serum adiponectin concentration was positively correlated with Rd (r = 0.52, P < 0.01) and the rate of glycogen synthesis (r = 0.36, P < 0.05), and was negatively correlated with free fatty acid level (r = -0.41, P < 0.05). (4) Stepwise regression analysis indicated that in addition to sex, BMI, WHR or VA and SA, serum adiponectin level was also the independent contributing factor for Rd, which explains 3.52% and 4.84% of the variance respectively (P all < 0.05). CONCLUSION: (1) The decrease in serum adiponectin level is associated with the increase of total body fat depot, especially the increase of total body fat depot in intra-abdominal fat area. (2) Serum adiponectin level is an independent contributing factor for insulin sensitivity.