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Value of the intravenous and oral glucose tolerance tests for detecting subtle impairments in insulin sensitivity and beta‐cell function in former gestational diabetes
Author(s) -
Tura A.,
Mari A.,
Prikoszovich T.,
Pacini G.,
KautzkyWiller A.
Publication year - 2008
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.2008.03178.x
Subject(s) - medicine , endocrinology , impaired glucose tolerance , gestational diabetes , insulin , diabetes mellitus , glucose tolerance test , insulin sensitivity , insulin resistance , type 2 diabetes , beta cell , gestation , pregnancy , biology , islet , genetics
Summary Objective Women with former gestational diabetes mellitus (fGDM) often show defects in both insulin sensitivity and beta‐cell function but it is not clear which defect plays the major role or which appears first. This might be because fGDM women are often studied as a unique group and not divided according to their glucose tolerance. Different findings might also be the result of using different tests. Our aim was to study insulin sensitivity and beta‐cell function with two independent glucose tolerance tests in fGDM women divided according to their glucose tolerance. Design and patients A total of 108 fGDM women divided into normal glucose tolerance (IGT; N = 82), impaired glucose metabolism (IGM; N = 20) and overt type 2 diabetes (T2DM; N = 6) groups, and 38 healthy control women (CNT) underwent intravenous (IVGTT) and oral glucose tolerance tests (OGTT). Measurements Insulin sensitivity and beta‐cell function were assessed by both the IVGTT and the OGTT. Results Both tests revealed impaired insulin sensitivity in the normotolerant group compared to controls (IVGTT: 4·2 ± 0·3 vs. 5·4 ± 0·4 10 −4 min −1 (µU/ml) −1 ; OGTT: 440 ± 7 vs. 472 ± 9 ml min −1 m −2 ). Conversely, no difference was found in beta‐cell function from the IVGTT. However, some parameters of beta‐cell function by OGTT modelling analysis were found to be impaired: glucose sensitivity (106 ± 5 vs. 124 ± 7 pmol min −1 m −2 m m −1 , P = 0·0407) and insulin secretion at 5 m m glucose (168 ± 9 vs. 206 ± 10 pmol min −1 m −2 , P = 0·003). Conclusions Both insulin sensitivity and beta‐cell function are impaired in normotolerant fGDM but the subtle defect in beta‐cell function is disclosed only by OGTT modelling analysis.