Nocturnal blood glucose and IGFBP-1 changes in type 1 diabetes: Differences in the dawn phenomenon between insulin regimens.
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.


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.
Yagasaki
H
H
Department of Pediatrics, University of Yamanashi, Japan. yagasaki@mwd.biglobe.ne.jp
Kobayashi
K
K
Saitou
T
T
Nagamine
K
K
Mitsui
Y
Y
Mochizuki
M
M
Kobayashi
K
K
Cho
H
H
Ohyama
K
K
Amemiya
S
S
Nakazawa
S
S
D000293:Adolescent; D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism*; D002940:Circadian Rhythm / Q000502:physiology; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism; D005260:Female; D006801:Humans; D007328:Insulin / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000069036:Insulin Glargine; D007332:Insulin Infusion Systems; D007336:Insulin, Isophane / Q000008:administration & dosage* / Q000627:therapeutic use; D049528:Insulin, Long-Acting; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008297:Male
D001786:Blood Glucose; D007328:Insulin; D049528:Insulin, Long-Acting; D018970:Insulin-Like Growth Factor Binding Protein 1; D000069036:Insulin Glargine; D007336:Insulin, Isophane; D007334:Insulin-Like Growth Factor I