Demonstration of glycated insulin in human diabetic plasma and decreased biological activity assessed by euglycemic-hyperinsulinemic clamp technique in humans

S.J. Hunter, A.C. Boyd, F.P.M. O'Harte, A.M. McKillop, M.I. Wiggam, Mark Mooney, J.T. McCluskey, C.N. Ennis, R. Gamble, B. Sheridan, C.R. Barnett, H. McNulty, Patrick M Bell, P.R. Flatt, John Lindsay

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Abstract

The presence and biological significance of circulating glycated insulin has been evaluated by high-pressure liquid chromatography (HPLC), electrospray ionization mass spectrometry (ESI-MS), radioimmunoassay (RIA), receptor binding, and hyperinsulinemic-euglycemic clamp techniques. ESI-MS analysis of an HPLC-purified plasma pool from four male type 2 diabetic subjects (HbA(1e) 8.1 +/- 0.2%, plasma glucose 8.7 +/- 1.3 mmol/l [means +/- SE]) revealed two major insulin-like peaks with retention times of 14-16 min. After spectral averaging, the peak with retention time of 14.32 min exhibited a prominent triply charged (M+3H)(3+) species at 1,991.1 m/z, representing monoglycated insulin with an intact M-r of 5,970.3 Da. The second peak (retention time 15.70 min) corresponded to native insulin (M-r 5,807.6 Da), with the difference between the two peptides (162.7 Da) representing a single glucitol adduct (theoretical 164 Da). Measurement of glycated insulin in plasma of type 2 diabetic subjects by specific RIA gave circulating levels of 10.1 +/- 2.3 pmol/l, corresponding to -9% total insulin. Biological activity of pure synthetic monoglycated insulin (insulin B-chain Phe(1)-glucitol adduct) was evaluated in seven overnight-fasted healthy nonobese male volunteers using two-step euglycemic-hyperinsulinemic clamps (2 h at 16.6 mug (.) kg(-1) (.) min(-1), followed by 2 h at 83.0 mug (.) kg(-1) (.) min(-1); corresponding to 0.4 and 2.0 mU (.) kg(-1) (.) min(-1)). At the lower dose, the exogenons glucose infusion rates required to maintain euglycemia during steady state were significantly lower with glycated insulin (P
Original languageEnglish
Pages (from-to)492-498
Number of pages7
JournalDiabetes
Volume52
Issue number2
Publication statusPublished - 01 Feb 2003

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Internal Medicine

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    Hunter, S. J., Boyd, A. C., O'Harte, F. P. M., McKillop, A. M., Wiggam, M. I., Mooney, M., McCluskey, J. T., Ennis, C. N., Gamble, R., Sheridan, B., Barnett, C. R., McNulty, H., Bell, P. M., Flatt, P. R., & Lindsay, J. (2003). Demonstration of glycated insulin in human diabetic plasma and decreased biological activity assessed by euglycemic-hyperinsulinemic clamp technique in humans. Diabetes, 52(2), 492-498.