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Study of In Vivo Glucose Metabolism in High-fat Diet-fed Mice Using Oral Glucose Tolerance Test (OGTT) and Insulin Tolerance Test (ITT)
Published on: January 7, 2018
Decreased beta cell function and insulin sensitivity contributed to increasing fasting glucose in Chinese
Yan Bi1, Dalong Zhu, Yali Jing
1Department of Endocrinology, Drum Tower Hospital Affiliated to Nanjing University Medical School, Zhongshan Road 321, 210008 Nanjing, China.
Acta Diabetologica
|May 18, 2010
Summary
Insulin resistance and impaired beta cell function contribute to rising fasting plasma glucose (FPG) even within the normal range. These issues begin early, preceding impaired fasting glucose and type 2 diabetes mellitus development.
Area of Science:
- Endocrinology
- Metabolic Syndrome Research
- Diabetes Pathophysiology
Background:
- Fasting plasma glucose (FPG) is a key indicator of glucose metabolism.
- Insulin resistance and beta cell dysfunction are central to type 2 diabetes mellitus (T2DM) pathogenesis.
- Understanding the early stages of these dysfunctions is crucial for timely intervention.
Purpose of the Study:
- To investigate the roles of insulin resistance and beta cell function in the progression of fasting plasma glucose.
- To determine if these dysfunctions manifest even at normal FPG levels.
Main Methods:
- Oral glucose tolerance test (OGTT) was used to categorize 1,272 Chinese subjects into NGT, IFG, IGT, CGI, and T2DM groups.
- Insulin sensitivity was assessed using the Matsuda index (ISI(M)) and 1/HOMA-IR.
- Beta cell function, adjusted for insulin sensitivity, was evaluated using disposition indices (DI(0), DI(30), DI(120)).
Main Results:
- Subjects with impaired fasting glucose (IFG) showed significantly decreased insulin sensitivity (ISI(M)) and disposition indices (DI(0), DI(30), DI(120)) compared to normal glucose tolerance (NGT).
- Declines in ISI(M) and DI were observed across increasing FPG categories, starting from the normal glucose range.
- Inverse correlations were found between ISI(M), DI, and FPG concentration (P < 0.001).
Conclusions:
- Both impaired beta cell function and insulin sensitivity begin to manifest at the lower end of the normoglycemic FPG range.
- These early dysfunctions contribute significantly to the deterioration of fasting glucose levels.
- Early detection and management of insulin resistance and beta cell dysfunction are vital for preventing T2DM.
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