Disproportionately elevated proinsulinemia is observed at modestly elevated glucose levels within the normoglycemic range

作者：Lorenzo Carlos^*; Hanley Anthony J; Rewers Marian J; Haffner Steven M

来源：ACTA DIABETOLOGICA, 2014, 51(4): 617-623.

DOI：10.1007/s00592-014-0565-3

• Proinsulinemia
• C-peptide
• Insulin sensitivity
• Insulin secretion
• Type 2 diabetes

We aimed to evaluate disproportional proinsulinemia in the pre-diabetic state by analyzing the cross-sectional differences between proinsulin (PI) ratios across the entire range of fasting and 2-h plasma glucose. The study sample was 1,016 participants in the insulin resistance atherosclerosis study, who had no previous diagnosis of diabetes. Insulin sensitivity index (S-I) and acute insulin response (AIR) were measured by the frequently sampled intravenous glucose tolerance test. Fasting intact and split PI-to-insulin ratios (PI/I, SPI/I), intact and split PI-to-C-peptide ratios (PI/C-pep, SPI/C-pep), and S-I-adjusted AIR were assessed as a function of fasting and 2-h glucose levels. S-I-adjusted AIR was decreased (fasting glucose 96-98 mg/dl; 2-h glucose 120-131 mg/dl) and SPI/C-pep increased at modestly elevated fasting glucose and 2-h glucose within the normal glucose tolerance range (fasting glucose 96-98 mg/dl; 2-h glucose 132-142 mg/dl). PI/I was not increased until plasma glucose values were in the diabetic range of fasting glucose (%26gt; 126 mg/dl) or the impaired glucose tolerance range of 2-h glucose (143-156 mg/dl). SPI/I and PI/C-pep as a function of fasting and 2-h glucose were situated between the curves for SPI/C-pep and PI/I. In conclusion, inappropriate amounts of PI and conversion intermediaries are demonstrated at modestly elevated glucose levels within the normoglycemic range. Ratios that use SPI in the numerator or C-pep in the denominator (and especially SPI/C-pep) are more sensitive to early glycemic excursions than PI/I. Disordered processing of PI may accompany derangements in early insulin secretory response.

• 出版日期2014-8