ETHNIC DIFFERENCES IN INSULIN SENSITIVITY

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 非裔美国人的2型糖尿病发病率高于高加索美国人。主要研究人员和其他研究小组的数据表明，非洲裔美国人与高加索美国人相比，对胰岛素的敏感性较低，而葡萄糖刺激的胰岛素浓度较高。这些差异可能有助于观察到疾病发生的种族差异。然而，胰岛素敏感性、分泌和清除方面潜在的种族差异的性质还没有完全确定。拟议的项目将：1)表征非裔美国人和高加索裔美国人的胰岛素敏感性、分泌和清除，以及2)确定胰岛素敏感性低下(更大的胰岛素抵抗)或高胰岛素血症可能是导致非裔美国人更大疾病风险的主要生理差异。所有受试者都将是女性，因为2型糖尿病对青少年非裔美国女孩和成年非裔美国女性的影响不成比例。将根据种族(高加索裔美国人、非裔美国人)、年龄(青春期前、青年、绝经后)和肥胖状况(非肥胖、肥胖)组成六个小组。共有180名受试者将作为住院患者在GCRC接受测试。测试将包括频繁采样的静脉葡萄糖耐量试验(FSIGT)，包括稳定同位素标记的葡萄糖、C肽测定和最小建模。身体成分和脂肪分布将分别通过双能X射线吸收测量法和计算机断层扫描确定。 需要检验的具体假设是：非洲裔美国人与高加索裔美国人相比，胰岛素敏感性较低是由于肝脏胰岛素提取(清除量)较低；由此产生的慢性高胰岛素血症最终导致外周(骨骼肌)胰岛素抵抗。 GCRC将在检测前提供饮食控制(生物营养)；进行FSIGT(护理)；处理血液样本(加工实验室)；分析样本的激素和底物(生理学和代谢核心实验室)。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The incidence of type 2 diabetes among African-Americans is greater than among Caucasian-Americans. Data from the principal investigator and other groups has suggested that insulin sensitivity is lower, and glucose-stimulated insulin concentration is higher, among African-Americans vs Caucasian Americans. These differences may contribute to observed ethnic differences in disease occurrence. However, the nature of potential ethnic differences in insulin sensitivity, secretion, and clearance has not been thoroughly determined. The proposed project will: 1) characterize insulin sensitivity, secretion, and clearance in African-Americans and Caucasian-Americans, and 2) determine whether depressed insulin sensitivity (greater insulin resistance) or hyperinsulinemia is likely to be the primary physiological difference conferring greater disease risk to African-Americans. All subjects will be female because type 2 diabetes disproportionately affects adolescent African-American girls and adult African-American women. Six groups will be formed based on ethnicity (Caucasian-American, African-American), age (prepubertal, young adult, postmenopausal), and obesity status (non-obese, obese). A total of 180 subjects will be tested as inpatients in the GCRC. Testing will consist of a frequently-sampled, intravenous, glucose tolerance test (FSIGT) incorporating stable-isotopically-labeled glucose, C-peptide determination, and minimal modeling. Body composition and fat distribution will be determined by dual-energy X-ray absorptiometry and computed tomography, respectively. The specific hypothesis to be tested is: Lower insulin sensitivity in African-Americans vs Caucasian-Americans is due to lower hepatic insulin extraction (clearance); the resultant chronic hyperinsulinemia ultimately results in peripheral (skeletal muscle) insulin resistance. The GCRC will provide dietary control prior to testing (Bionutrition); perform the FSIGT (Nursing); process the blood samples (Processing Laboratory); and analyze samples for hormones and substrates (Physiology and Metabolism Core Laboratory).