Demonstration of increased concentrations of circulating glycated insulin in human Type 2 diabetes using a novel and specific radioimmunoassay.
OBJECTIVE
Glycation of insulin, resulting in impaired bioactivity, has been shown within pancreatic beta cells. We have used a novel and specific radioimmunoassay to detect glycated insulin in plasma of Type 2 diabetic subjects.


METHODS
Blood samples were collected from 102 Type 2 diabetic patients in three main categories: those with good glycaemic control with a HbA(1c) less than 7%, moderate glycaemic control (HbA(1c) 7-9%) and poor glycaemic control (HBA(1c) greater than 9%). We used 75 age- and sex-matched non-diabetic subjects as controls. Samples were analysed for HbA(1c), glucose and plasma concentrations of glycated insulin and insulin.


RESULTS
Glycated insulin was readily detected in control and Type 2 diabetic subjects. The mean circulating concentration of glycated insulin in control subjects was 12.6+/-0.9 pmol/l ( n=75). Glycated insulin in the good, moderate and poorly controlled diabetic groups was increased 2.4-fold ( p<0.001, n=44), 2.2-fold ( p<0.001, n=41) and 1.1-fold ( n=17) corresponding to 29.8+/-5.4, 27.3+/-5.7 and 13.5+/-2.9 pmol/l, respectively.


CONCLUSIONS
Glycated insulin circulates at noticeably increased concentrations in Type 2 diabetic subjects.
Regional Centre for Endocrinology, Royal Victoria Hospital, Belfast, Northern Ireland, UK.
J R
JR
Lindsay
A M
AM
McKillop
M H
MH
Mooney
F P M
FP
O'Harte
P M
PM
Bell
P R
PR
Flatt
D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005260:Female; D017127:Glycation End Products, Advanced; D006031:Glycosylation; D006801:Humans; D007328:Insulin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay / Q000379:methods*; D012709:Serum Albumin; D000093423:Glycated Serum Albumin
D017127:Glycation End Products, Advanced; D007328:Insulin; D012709:Serum Albumin; D000093423:Glycated Serum Albumin