The plasma insulin concentration during 50gm. oral glucose tolerance test was measured in 6 normal and 12 untreated diabetic subjects using the Insulin Immunoassay Kit modified from Double Antibody Immunoassay Method of Hales and Randle(1963). and the following results were obtained.
1. The plasma insulin concentration in normal subject was at fasting 13.0±2.8 microunit/㎖, and 30, 60, 90 and 120 minutes after oral glucose load, 25.5±4.0, 33.7±1.8, 31.8±3.8 and 19.0±5.5 microunit/㎖ respectively.
2. The plasma insulin concentration of mild diabetic subjects after the oral glucose load was similar to that of normal subjects and showed the tendency of delayed insulin response.
3. The diabetic subjects with high blood sugar level had a low insulin response while those with relatively low blood sugar level had a more normal insulin response.
4. The relatively low plasma insulin concentration compared with those reported by other workers was thought to be related to dietary habits and ethnic specificity.