应用高葡萄糖钳夹技术检测肥胖伴糖耐量异常者胰岛β细胞的功能变化

目的　应用高葡萄糖钳夹技术探讨糖耐量异常 (IGT)及糖尿病 (DM )个体胰岛素分泌功能的改变 ,以及与超重 /肥胖 (OW /OB)的关系。方法　根据糖耐量情况将上海地区 6 4例受试者分为正常糖耐量 (NGT)组、IGT组及DM组 ;再以体重指数 2 5kg/m2 为切割点 ,把不同糖耐量的受试者分成 6个组 :正常体重 (NW )NGT(NW NGT)组、NW IGT组、NW DM组、OW /OB NGT组、OW /OB IGT组、及OW /OB DM组。应用高葡萄糖钳夹技术研究IGT及DM个体各时相胰岛素分泌指数。结果　 (1)IGT及DM个体胰岛素分泌形态的变化表现 :第一时相胰岛素分泌进行性降低 (IGT 186mU/L± 38mU/L ,DM 71mU/L± 10mU/L ,P <0 0 5 ) ;第二时相胰岛素分泌明显减退 (IGT 70mU/L± 14mU/L ,DM 32mU/L± 4mU/L ,P <0 0 5 )。 (2 )NW IGT及NW DM者 ,第一时相 (NW IGT16 4mU/L± 4 7mU/L ,NW DM 6 1mU/L± 17mU/L)、第二时相 (NW IGT 4 4mU/L± 18mU/L ,NW DM 2 6mU/L± 5mU/L)及最大胰岛素分泌功能 (NW IGT 5 3mU/L± 2 1mU/L ,NW DM 34mU/L± 6mU/L)均显著减退 (P <0 .0 5 )。 (3)单纯OW /OB个体第一、第二时相胰岛素分泌指数及最大胰岛素分泌量显著高于NW NGT者 (分别为 5 4 6mU/L± 6 2mU/L、138mU/L± 18mU/L、16 3mU/L± 2 4mU/L ,P <0 0 5 ) ,OW /O

Application of hyperglycemic clamp technique in the assessment of beta-cell function in obese individuals with glucose intolerance

OBJECTIVE: To study the changes of insulin secretion in Chinese individuals with impaired glucose tolerance and diabetes and the relationship between insulin release and overweight/obesity. METHODS: Sixty-four individuals were divided into 6 groups according to glucose tolerance (GT) and body weight: normal weight with normal glucose tolerance (NW-NGT) group, NW with impaired glucose tolerance (NW-IGT) group, NW with diabetes (NW-DM) group, overweight or obese (OW/OB) with NGT (OW/OB-NGT) group, OW/OB with IGT (OW/OB-IGT) group, OW/OB with DM (OW/OB-DM) group. The subjects were required to fast for 12 hours and then underwent oral glucose tolerance test (OGTT) and hyperglycemic clamp. RESULTS: 1. The first-phase insulin release, the sum of insulin concentrations during the first 10 minutes (at the 2(nd), 4(th), 6(th), 8(th), and 10(th) minutes) were 186 mU/L +/- 38 mU/L in the IGT groups, significantly lower than that of the NGT groups (P = 0.001). The first-phase insulin release of the DM groups was 71 mU/L +/- 10 mU/L, significantly lower than those of the NW-NGT group and IGT group (257 mU/L +/- 22 mU/L and 164 mU/L +/- 47 mU/L respectively, both P < 0.01). The second-phase insulin release, the average insulin concentration during the 20th to 150th minutes of the DM groups was 31 mU/L +/- 4 mU/L, significantly lower than those of the NGT and IGT groups (74 mU/L +/- 5 mU/L and 45 mU/L +/- 19 mU/L, P < 0.01 and P < 0.04). The 2nd-phase insulin release was not significantly different between the NGT and IGT groups (P = 0.13). The maximum insulin release (INS-Max), the average insulin concentration during the last 30 minutes (120th to 150th minutes), of the DM groups was 40 mU/L +/- 6 mU/L, significantly lower than those of the NGT and IGT groups (P < 0.05). The INS-MAX was not significantly different between the NGT and IGT groups (P = 0.12). The first-phase insulin release, second-phase insulin release, and INS-MAX of the NW-IGT group were 164 mU/L +/- 47 mU/L, 45 mU/L +/- 19 mU/L, and 53 mU/L +/- 22 mU/L respectively, all significantly higher than those of the NW-IGT group (61 mU/L +/- 17 mU/L, 27 mU/L +/- 5 mU/L, and 34 mU/L +/- 6 mU/L respectively, P < 0.05) and those of the DM groups (61 mU/L +/- 17 mU/L, 27 mU/L +/- 5 mU/L, and 34 mU/L +/- 6 mU/L respectively, P < 0.05). 3. The first-phase insulin release, second-phase insulin release, and INS-MAX of the OW/OB-NGT group were 546 mU/L +/- 62 mU/L, 138 mU/L +/- 18 mU/L, and 163 mU/L +/- 24 mU/L respectively, all significantly higher than those of the NW-NGT group (257 mU/L +/- 22 mU/L, 74 mU/L +/- 6 mU/L, and 97 mU/L +/- 8 mU/L, respectively, P < 0.05). The first- phase insulin secretion in the OW/OB-IGT group and OW/OB-DM group were 201 mU/L +/- 47 mU/L and 82 mU/L +/- 9 mU/L respectively, both significantly lower than that of the OW/OB- NGT group (P < 0.05). CONCLUSION: 1. The insulin release is progressively decreased in Chinese individuals with IGT and DM. The individuals with IGT have lower first phase insulin release. In addition to decreased first phase insulin release, subjects with DM have reduced second-phase and maximum insulin release. 2. Simply overweight/obese individuals have higher insulin secretion, while overweight or obese individuals with IGT and DM have reduced first phase insulin release.