Increment of serum C-peptide measured by glucagon test closely correlates with human relative beta-cell area

Yukari Fujita, Junji Kozawa, Hiromi Iwahashi, Syo Yoneda, Sae Uno, Atsushi Yoshikawa, Kohei Okita, Hidetoshi Eguchi, Hiroaki Nagano, Akihisa Imagawa, Iichiro Shimomura

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15 Citations (Scopus)

Abstract

Pancreatic beta-cell mass contributes to glucose tolerance. The aim of this study was to evaluate the relationships between human beta-cell mass and various clinical parameters, including insulin secretory capacity. The study included 32 Japanese patients who underwent pancreatectomy and were naive to oral hypoglycemic agents and insulin. They were classified into those with normal glucose tolerance (n=13), impaired glucose tolerance (n=9) and diabetes (n=10), and their insulin secretory capacity and insulin resistance were evaluated. Immunohistochemistry was used to determine relative beta-cell area (%) which represented the proportion of insulin-positive cell area to whole pancreatic section. Increment of C-peptide immunoreactivity level by glucagon test (ΔC-peptide, increment of serum C-peptide [nmol/L] at 6 min after intravenous injection of 1-mg glucagon; r=0.64, p=0.002), homeostasis model assessment of beta-cell function (HOMAbeta, fasting immunoreactive insulin [µIU/mL] x 20 / (fasting plasma glucose [mmol/L] – 3.5); r=0.50, p=0.003), C-peptide index (CPI, fasting C-peptide [nmol/L] / fasting plasma glucose [mmol/L]; r=0.36, p=0.042), and fasting immunoreactive insulin (F-IRI [pmol/L]; r=0.36, p=0.044) correlated significantly and positively with the relative beta-cell area. The area under the curve of plasma glucose level from 0 to 120 min by 75 g-OGTT (AUC0-120) also correlated significantly and inversely with the relative beta-cell area (r=–0.36, p=0.045). Stepwise multiple regression analysis identified ΔC-peptide as the only independent and significant determinant of the relative beta-cell area. We conclude that ΔC-peptide, HOMAbeta, CPI, F-IRI and AUC0-120 correlated closely with the relative beta-cell area, and ΔC-peptide was the most valuable index for the prediction of the area.

Original languageEnglish
Pages (from-to)329-337
Number of pages9
JournalEndocrine Journal
Volume62
Issue number4
DOIs
Publication statusPublished - 2015

All Science Journal Classification (ASJC) codes

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

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    Fujita, Y., Kozawa, J., Iwahashi, H., Yoneda, S., Uno, S., Yoshikawa, A., Okita, K., Eguchi, H., Nagano, H., Imagawa, A., & Shimomura, I. (2015). Increment of serum C-peptide measured by glucagon test closely correlates with human relative beta-cell area. Endocrine Journal, 62(4), 329-337. https://doi.org/10.1507/endocrj.EJ14-0456