Meal-induced 24-hour profile of circulating glycated insulin in type 2 diabetic subjects measured by a novel radioimmunoassay

• Published in: Metabolism, clinical and experimental clinical and experimental, 2003-05, Vol.52 (5), p.631-635
• Main Authors: Lindsay, John R., McKillop, Aine M., Mooney, Mark H., Flatt, Peter R., Bell, Patrick M., O'Harte, Finbarr P.M.
• Format: Article
• Language: English
• Subjects: Associated diseases and complications; Biological and medical sciences; Blood Glucose - metabolism; Circadian Rhythm; Diabetes Mellitus, Type 2 - blood; Diabetes. Impaired glucose tolerance; Diet; Eating - physiology; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Enzyme-Linked Immunosorbent Assay; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Female; Glycosylation; Homeostasis - physiology; Humans; Insulin - blood; Male; Medical sciences; Middle Aged; Postprandial Period - physiology; Radioimmunoassay
• ISSN: 0026-0495; 1532-8600
• DOI: 10.1053/meta.2003.50150

Increasing evidence supports a role for glycated insulin in the insulin-resistant state of type 2 diabetes. We measured 24-hour profiles of plasma glycated insulin, using a novel radioimmunoassay (RIA), to evaluate the effects of meal stimulation and intermittent fasting on circulating concentrations of plasma glycated insulin in type 2 diabetes. Patients (n = 6; hemoglobin A1c [HbA1c], 7.2% ± 0.6%; fasting plasma glucose, 7.4 ± 0.7 mmol/L; body mass index [BMI], 35.7 ± 3.5 kg/m2; age, 56.3 ± 4.4 years) were admitted for 24 hours and received a standardized meal regimen. Half-hourly venous samples were taken for plasma glycated insulin, glucose, insulin, and C-peptide concentrations between 8 am and midnight and 2-hourly overnight. The mean plasma glycated insulin concentration over 24 hours was 27.8 ± 1.2 pmol/L with a mean ratio of insulin:glycated insulin of 11:1. Circulating glucose, insulin, C-peptide, and glycated insulin followed a basal and meal-related pattern with most prominent increments following breakfast, lunch, and evening meal, respectively. The mean concentrations of glycated insulin during the morning, afternoon, evening, and night-time periods were 24.4 ± 2.5, 28.7 ± 2.3, 31.1 ± 2.1, and 26.2 ± 1.5 pmol/L, respectively, giving significantly higher molar ratios of insulin:glycated insulin of 18.0:1, 14.2:1, and 12.7:1 compared with 7.0:1 at night (P