Higgins Paul B, Férnández José R, Garvey W Timothy, Granger Wesley M, Gower Barbara A
Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA.
Am J Clin Nutr. 2008 Nov;88(5):1277-83. doi: 10.3945/ajcn.2008.26357.
African Americans have a greater insulin response after glucose challenge than do European Americans. Factors underlying this response are unknown.
We determined the insulin, C-peptide, and incretin responses to a mixed macronutrient meal in African American and European American children. We hypothesized that 1) African Americans would have greater postprandial insulin and C-peptide responses, 2) African Americans would have higher incretin responses, and 3) the greater beta cell response among African Americans would be explained by greater incretin responses.
Subjects were 34 African American and 18 European American children. Glucose, insulin, C-peptide, glucagon-like peptide-1 (GLP-1), and glucose-dependent insulinotropic polypeptide (GIP) were measured after the subjects consumed a liquid mixed meal. Insulin, C-peptide, and incretin responses were derived from the area under the curve (AUC) for minutes 0-30 (early response) and minutes 30-180 (late response) after meal ingestion.
The early insulin response was higher in African American (14,565 +/- 6840 pmol/L x 30 min) than in European American (7450 +/- 4077 pmol/L x 30 min; P < 0.01) children. Early C-peptide AUC did not differ by ethnicity (African Americans: 34.8 +/- 12.5; European Americans: 28.6 +/- 12.5 nmol/L x 30 min; P = 0.10). Early and late GLP-1 responses were lower in African Americans than in European Americans: 108.1 +/- 56.4 compared with 160.5 +/- 90.8 pmol/L x 30 min and 509.4 +/- 286.9 compared with 781.9 +/- 483.4 pmol/L x 150 min, respectively (P < 0.05 for both). The GIP response did not differ between groups.
The greater early insulin response in African Americans than in European Americans is not due to differences in circulating GLP-1 or GIP and may be due to lesser insulin clearance. Further research is needed to determine the physiologic implications of lower GLP-1 among African Americans.
非裔美国人在葡萄糖耐量试验后的胰岛素反应比欧裔美国人更强。这种反应背后的因素尚不清楚。
我们测定了非裔美国儿童和欧裔美国儿童对混合宏量营养素餐的胰岛素、C肽和肠促胰岛素反应。我们假设：1）非裔美国人的餐后胰岛素和C肽反应更强；2）非裔美国人的肠促胰岛素反应更高；3）非裔美国人中更强的β细胞反应可以用更高的肠促胰岛素反应来解释。
研究对象为34名非裔美国儿童和18名欧裔美国儿童。在受试者食用液体混合餐后，测量血糖、胰岛素、C肽、胰高血糖素样肽-1（GLP-1）和葡萄糖依赖性促胰岛素多肽（GIP）。胰岛素、C肽和肠促胰岛素反应通过餐后0 - 30分钟（早期反应）和30 - 180分钟（晚期反应）的曲线下面积（AUC）得出。
非裔美国儿童（14,565±6840 pmol/L×30分钟）的早期胰岛素反应高于欧裔美国儿童（7450±4077 pmol/L×30分钟；P<0.01）。早期C肽AUC在不同种族间无差异（非裔美国人：34.8±12.5；欧裔美国人：28.6±12.5 nmol/L×30分钟；P = 0.10）。非裔美国人的早期和晚期GLP-1反应低于欧裔美国人：分别为108.1±56.4与160.5±90.8 pmol/L×30分钟，以及509.4±286.9与781.9±483.4 pmol/L×150分钟（两者P均<0.05）。两组间GIP反应无差异。
非裔美国人比欧裔美国人更强的早期胰岛素反应并非由于循环GLP-1或GIP的差异，可能是由于胰岛素清除率较低。需要进一步研究以确定非裔美国人中较低GLP-1的生理意义。
