The serum levels of proinsulin and their relationship with IGFBP-1 in obese children

  1. T. Kamoda*,
  2. H. Saitoh,
  3. M. Inudoh,
  4. K. Miyazaki,
  5. A. Matsui

Article first published online: 18 MAR 2005

DOI: 10.1111/j.1463-1326.2005.00479.x

Issue

Diabetes, Obesity and Metabolism

Diabetes, Obesity and Metabolism

Volume 8, Issue 2, pages 192–196, March 2006

Additional Information

How to Cite

Kamoda, T., Saitoh, H., Inudoh, M., Miyazaki, K. and Matsui, A. (2006), The serum levels of proinsulin and their relationship with IGFBP-1 in obese children. Diabetes, Obesity and Metabolism, 8: 192–196. doi: 10.1111/j.1463-1326.2005.00479.x

Author Information

  1. Department of Pediatrics, University of Tsukuba, Ibaraki, Japan

* *Tomohiro Kamoda, MD, Department of Pediatrics, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8575, Ibaraki, Japan. E-mail: tkamoda@md.tsukuba.ac.jp

Publication History

  1. Issue published online: 18 MAR 2005
  2. Article first published online: 18 MAR 2005
  3. Received 18 March 2004; returned for revision 31 October 2004; revised version accepted 5 December 2004

SEARCH

SEARCH BY CITATION

ARTICLE TOOLS

View Full Article (HTML) Get PDF (82K)

Keywords:

  • children;
  • IGFBP-1;
  • insulin resistance;
  • obesity;
  • proinsulin

Aim:  Serum proinsulin (PI) levels were investigated in obese children to determine whether PI is a sensitive indicator of insulin resistance, as previously shown in adults with type 2 diabetes mellitus (DM), and to evaluate their relationship with insulin-like growth factor-binding protein-1 (IGFBP-1) known as a predictor of the development of cardiovascular disease in diabetic adults.

Subjects and methods:  Forty-two obese children without DM (age, 12.1 ± 1.5 year) and 42 age-matched control children were included in the study. The serum levels of PI, immunoreactive insulin (IRI), IGFBP-1 and free insulin-like growth factor-1 (IGF-1) were measured in the fasting state.

Results:  The fasting levels of serum PI and IRI were significantly higher in obese children than in controls (PI, 10.5 ± 6.8 vs. 5.6 ± 2.0 pmol/l, p < 0.001; IRI, 72.0 ± 41.8 vs. 32.7 ± 19.5 pmol/l, p < 0.001). Serum IGFBP-1 levels were significantly lower in obese children than in controls (37.7 ± 24.6 vs. 76.3 ± 26.5 µg/l, p < 0.001). The ratio of PI to IRI (calculated as molar ratios) did not differ significantly between obese and control subjects (0.16 ± 0.08 vs. 0.19 ± 0.11, p = 0.08). For the whole group, serum PI levels correlated positively with IRI and inversely with IGFBP-1 (IRI, r = 0.67, p < 0.001; IGFBP-1, r = −0.49, p < 0.001). Serum IGFBP-1 levels correlated inversely with both BMI and IRI (BMI, r = −0.73, p < 0.001; IRI, r = −0.60, p < 0.001). Multiple regression analysis revealed that the best predictive parameters for IGFBP-1 were BMI and PI (R2 = 0.57, p < 0.001 and p < 0.05, respectively).

Conclusion:  These findings suggest that fasting serum PI levels may be a better predictor than fasting insulin levels for the future development of type 2 DM and cardiovascular disease in obese children, and PI, in addition to insulin, contributes to the suppression of hepatic IGFBP-1 production.

View Full Article (HTML) Get PDF (82K)