Ethnic variability in the plasma insulin response to oral glucose in Polynesian and Micronesian subjects.

The pattern of insulin response to oral glucose over a wide range of glucose tolerance has been studied in two separate ethnic groups--Polynesians and Micronesians. Fasting insulin concentrations were relatively unchanged over the entire range of glucose tolerance in both populations, irrespective of whether comparable lean or obese samples of both groups were studied. The patterns of 2-h plasma insulins were similar over the whole range of glucose tolerance in Polynesians and Micronesians. However, in the comparisons of all subjects, or lean or obese groups of these populations, the plasma insulin concentrations of the Micronesians were both consistently and significantly higher. As the data analysis was arranged to take into account groups with identical 2-h plasma glucose concentrations and comparable degrees of obesity, the differences cannot be attributed to differences in the glucose levels or in obesity. In the presence of similar fasting insulin concentrations, these findings imply an ethnic variability in the pancreatic beta-cell response to oral glucose.