Insulin secretion during intravenous glucose tolerance tests in non-insulin-dependent diabetes in the young.

The phasic response of insulin to intravenous glucose was studied in 9 patients with non-insulin-dependent diabetes in the young (NIDDY), with 3-generation transmission of the disease; and 9 age-, weight- and sex-matched reference subjects. Furthermore, 10 non-diabetic siblings of these diabetic patients were submitted to the same test procedure in an attempt to identify a prodrome of impaired glucose tolerance. In comparison to the controls and non-diabetic family members, the diabetics had no first phase insulin release. In addition, the non-diabetic siblings had insulin and glucose responses similar to those of the reference subjects. Therefore, it would appear that there is no prodromal phase in this discrete syndrome of NIDDY.