Features and clinical implications of fasting intact proinsulin to insulin molar (P/I) ratio 1: P/I Ratio vs Pancreatic β cell function in type 2 diabetes mellitus and reference range in subjects with normal glucose tolerance

Shoji Kawazu, Masako Yazawa, Yasuo Imai, Hitoshi Horie, Yoshikazu Hisano, Yuhei Koyama, Hitoshi Ishida, Sachihiko Ozawa, Kiyoshi Suzuki, Yasuhiko Iwamoto, Hiroshi Sakura, Yasunori Kanazawa, Ryuzo Kawamori, Hiroshi Uchino, Tetsuro Kobayashi, Kaoru Aida, Shoichi Tomono, Shoichiro Nagasaka, Ikuro Matsuba, Taro MaruyamaYoshifumi Saisho, Takeshi Kuzuya

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Abstract

Using an Intact-Proinsulin Assay® (MLT Research Ltd.), we studied the clinical implications and usefulness of the plasma intact proinsulin to insulin molar ratio (P/I) ratio in morning fasting. Obese (BMI ≥ 25 kg/m 2) adults (age ≥30 years old) with normal glucose tolerance (NGT) had a significantly lower P/I ratio than nonobese adults with NGT. The P/I ratio reference range in nonobese adult NGT was 0.04- 0.31. In nonobese subjects with differing degrees of glucose tolerance, the P/I ratio increased significantly with glucose intolerance severity. The P/I ratio in subjects with type 2 diabetes mellitus treated with diet and exercise alone whose fasting glucose exceeded 126 mg/d/ was significantly higher than in those whose fasting glucose was less than 126 mg/dl. The P/I ratio correlated significant by inverse by with the insulinogenic index in the 75 g oral glucose tolerance test. We found that the P/I ratio is closely related to insulin secretory ability, and may be a simple, easy index for reflecting the impoverishment or functional decline in pancreatic β cells.

Original languageEnglish
Pages (from-to)537-545
Number of pages9
JournalJournal of the Japan Diabetes Society
Volume52
Issue number7
Publication statusPublished - 2009

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ASJC Scopus subject areas

  • Endocrinology
  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism

Cite this

Kawazu, S., Yazawa, M., Imai, Y., Horie, H., Hisano, Y., Koyama, Y., Ishida, H., Ozawa, S., Suzuki, K., Iwamoto, Y., Sakura, H., Kanazawa, Y., Kawamori, R., Uchino, H., Kobayashi, T., Aida, K., Tomono, S., Nagasaka, S., Matsuba, I., ... Kuzuya, T. (2009). Features and clinical implications of fasting intact proinsulin to insulin molar (P/I) ratio 1: P/I Ratio vs Pancreatic β cell function in type 2 diabetes mellitus and reference range in subjects with normal glucose tolerance. Journal of the Japan Diabetes Society, 52(7), 537-545.