Evidence of β cell dysfunction which does not lead on to diabetes: A study of identical twins of insulin dependent diabetics

Abstract

Ten non-diabetic identical twins of insulin dependent diabetics were studied to see whether they showed changes in insulin secretion. The twins were selected because (a) more than 11 years had elapsed since the diagnosis of the diabetic twin and they were therefore unlikely to develop diabetes, and (b) they had had islet cell antibodies. Despite similar glucose concentrations to the controls the twins had greater total immunoreactive insulin responses to both oral (mean 3280 (SD 699) versus 2338 (1110) pmol/dl at 180 minutes; p<0.05) and intravenous (1346 (690) versus 699 (294) pmol/dl at 30 minutes; p<0.05) glucose challenge. The C peptide responses to intravenous glucose were also increased consistent with increased insulin secretion. In addition, basal serum proinsulin concentrations in the twins were increased (2.1 (1.2) versus 1.0 (0.3) pmol/dl; p<0.01) and remained so throughout both tests. These twins, who were unlikely to develop insulin dependent diabetes, showed evidence of β cell dysfunction which does not progress to diabetes. © 1987, British Medical Journal Publishing Group. All rights reserved.