Plasma Retinol-Binding Protein-4 Concentrations Are Elevated in Human Subjects With Impaired Glucose Tolerance and Type 2 Diabetes
- Young Min Cho, MD, PHD12,
- Byung-Soo Youn, PHD34,
- Hyewon Lee, MS3,
- Namseok Lee, MS3,
- Sung-Shik Min, MS3,
- Soo Heon Kwak, MD12,
- Hong Kyu Lee, MD, PHD12 and
- Kyong Soo Park, MD, PHD12
- 1Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
- 2Genome Research Center for Diabetes and Endocrine Disease, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea
- 3AdipoGen, College of Life Science and Biotechnology, Korea University, Seoul, Korea
- 4Immunomodulation Research Center, University of Ulsan, Ulsan, Korea
- Address correspondence and reprint requests to Kyong Soo Park, MD, PhD, Department of Internal Medicine, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul, 110-744, Korea. E-mail: kspark{at}snu.ac.kr
Abstract
OBJECTIVE—The dysregulation of adipokines is closely associated with the pathogenesis of insulin resistance and type 2 diabetes. Retinol-binding protein-4 (RBP4), a new adipokine, was recently reported to provide a link between obesity and insulin resistance. Here, we examined the relation between plasma RBP4 concentrations and various metabolic parameters in humans.
RESEARCH DESIGN AND METHODS—An enzyme-linked immunosorbent assay was developed to measure human RBP4 plasma concentrations, which were then compared with various parameters related to insulin resistance in subjects with normal glucose tolerance (NGT; n = 57), impaired glucose tolerance (IGT; n = 48), and type 2 diabetes (n = 49).
RESULTS—Plasma RBP4 concentrations were higher in the IGT and type 2 diabetic groups than in the NGT group (median 18.9 [range 11.2–45.8], 20.9 [9.9–48.5], and 18.1 μg/ml [9.3–30.5], respectively). However, no difference was found between plasma RBP4 concentrations in the IGT and type 2 diabetic groups. Plasma RBP4 concentrations were found to be associated with sex, waist circumference, fasting plasma glucose, and insulin resistance. Of these, sex and fasting plasma glucose levels were found to be independent determinants of plasma RBP4 concentration.
CONCLUSIONS—Plasma RBP4 concentrations were found to be elevated in subjects with IGT or type 2 diabetes and to be related to various clinical parameters known to be associated with insulin resistance.
- ELISA, enzyme-linked immunosorbent assay
- HOMA-B, homeostasis model assessment of β-cell function
- HOMA-IR, homeostasis model assessment of insulin resistance
- IGT, impaired glucose tolerance
- NGT, normal glucose tolerance
- RBP4, retinol-binding protein-4
Footnotes
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Editor’s comment: This manuscript was in the process of review when another article with similar findings was published (N Engl J Med 354:2552–2563, 2006).
Y.M.C. and B.-S.Y. contributed equally to this work.
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C Section 1734 solely to indicate this fact.
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- Accepted August 3, 2006.
- Received February 13, 2006.
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