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Four weeks of near‐normalization of blood glucose has no effect on postprandial GLP‐1 and GIP secretion, but augments pancreatic B‐cell responsiveness to a meal in patients with Type 2 diabetes
Author(s) -
Højberg P. V.,
Vilsbøll T.,
Zander M.,
Knop F. K.,
Krarup T.,
Vølund A.,
Holst J. J.,
Madsbad S.
Publication year - 2008
Publication title -
diabetic medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.474
H-Index - 145
eISSN - 1464-5491
pISSN - 0742-3071
DOI - 10.1111/j.1464-5491.2008.02579.x
Subject(s) - postprandial , medicine , endocrinology , incretin , insulin , meal , type 2 diabetes , glucagon like peptide 1 , diabetes mellitus
Objective The aim of the present study was to investigate whether 4 weeks of near‐normalization of blood glucose (BG) improves incretin hormone secretion and pancreatic B‐cell function during a mixed meal. Research design and methods Nine patients with Type 2 diabetes in poor glycaemic control [glycated haemoglobin (HbA 1c ) 8.0 ± 0.4%] were investigated before and after 4 weeks of near‐normalization of BG (mean BG 6.4 ± 0.3 mmol/l) using insulin treatment. HbA 1c after insulin treatment was 6.6 ± 0.3%. For comparison, nine healthy control subjects were also studied. Postprandial glucagon‐like peptide 1 (GLP‐1) and glucose‐dependent insulinotropic polypeptide (GIP) incremental responses were assessed during a mixed meal test. Fasting and postprandial pancreatic B‐cell function was determined from calculations of insulin secretion rates in relation to plasma glucose. Results There was no difference in IAUC totalGLP‐1 or in IAUC totalGIP between the two experimental days. B‐cell sensitivity to glucose (insulinogenic index) did not differ before and after insulin treatment in the fasting state (0.21 ± 0.17 vs. 0.25 ± 0.10 pmol kg −1 min −1 /mmol l −1 ), but improved significantly during the first 30 min after start of the meal (0.28 ± 0.07 vs. 0.46 ± 0.06 pmol kg −1 min −1 /mmol l −1 ) and during the following 4 h (0.34 ± 0.09 vs. 0.56 ± 0.07 pmol kg −1 min −1 / mmol l −1 ). The B‐cell responsiveness to changes in plasma glucose, expressed as the slope of the linear relationship between the insulin secretion rate and the concomitant plasma glucose increased from 0.59 ± 0.16 to 0.94 ± 0.13 pmol kg −1 min −1 / mmol l −1 ( P < 0.07). Conclusions Four weeks of near‐normalization of BG had no effect on postprandial secretion of incretin hormones. Nevertheless, several parameters of meal‐induced insulin secretion improved after insulin treatment.