Related Experiment Video
Updated: Jun 19, 2026

Through-the-Wall Blood Sampling Method to Minimize Sleep Disruption in Clinical Settings
Published on: June 13, 2025
Nocturnal blood glucose and IGFBP-1 changes in type 1 diabetes: Differences in the dawn phenomenon between insulin
H Yagasaki1, K Kobayashi, T Saitou
1Department of Pediatrics, University of Yamanashi, Japan. yagasaki@mwd.biglobe.ne.jp
Objective:
Insulin-like growth factor binding protein-1 (IGFBP-1) is known to regulate the bioavailability of insulin-like growth factor (IGF) and the levels of IGFBP-1 are increased in the morning in patients with type 1 diabetes mellitus. We investigated the nocturnal fluctuations of glucose, IGFBP-1, and free IGF-1 levels with three insulin regimens.
Research Design And Methods:
Forty-eight type 1 diabetes patients were divided into three groups according to their basal insulin therapy (continuous subcutaneous insulin infusion [CSII], insulin glargine, NPH insulin). Blood samples were obtained every 2 h between 2 300 h and 0700 h to measure plasma glucose, IGFBP-1 and free IGF-1 levels.
Results:
The dawn phenomenon was more frequent with NPH (62.1%) than with glargine (16.6%, p<0.05) and CSII (14.3%, p<0.05). In the NPH group, the serum IGFBP-1 levels were markedly increased from 21.0+/-3.6 ng/ml at 2 300 h to 200.3+/-21.8 ng/ml at 0700 h and free IGF-1 levels were inversely decreased; these changes were partially suppressed in the CSII and glargine groups.
Conclusions:
The use of insulin regimens that provide sufficient insulin levels in the early morning can suppress the dawn phenomenon, leading to improved glycemic control. The increase in circulating IGFBP-1 in the morning, as a result of waning of insulin action, lowers free IGF-1 levels and may cause insulin resistance.
Related Concept Videos
Type I Diabetes III: Clinical Manifestations
Type I Diabetes II: Pathophysiology
Diabetes Mellitus: Type 2 and Gestational
Insulin: Dosing Regimen and Adverse Effects
The basal dose constitutes about 40%-50% of the total daily dose, with the rest as premeal insulin. The mealtime insulin dose should mirror...
Hormones Regulating Blood Glucose
In addition to accelerating glucose uptake and utilization, insulin has...
Type II Diabetes II: Pathophysiology
