INSULIN SECRETORY RESPONSE IN JAPANESE TYPE-2 (NON-INSULIN-DEPENDENT)DIABETIC-PATIENTS

Insulin (immunoreactive insulin, IRI) response during a 100 g oral glu cose tolerance test was studied in a large number of patients with def inite diabetes, equivocal diabetes, and other pathological states caus ing glucose intolerance. Definite diabetes was diagnosed in patients w ith overt fasting hyperglycemia. Once the diagnosis of definite diabet es was made, IRI response remained low after improvement of glucose to lerance. Glucose intolerance caused by other pathological extra-pancre atic conditions was usually accompanied by increased IRI response. IRI response in equivocal diabetes was variable, but almost always decrea sed in those who developed definite diabetes later. In subjects with a strong family history of type 2 diabetes, the prevalence of a low IRI response was high. In non-diabetic subjects, weight gain caused a mar ked increase in IRI response and a small increase in blood glucose, wh ile in those who developed diabetes, IRI increased little despite the marked increase in blood glucose. These data suggest that low IRI resp onse is an important feature of type 2 diabetes, perhaps with a heredi tary basis in part. It precedes the occurrence of overt hyperglycemia and persists after improvement of glucose tolerance.