Endocrine Abstracts

Introduction and aims: To date we have had some evidence that betatrophin is associated with insulin resistance. Some studies have demonstrated that betatrophin levels are elevated in type 2 diabetes, obesity and gestational diabetes. It has been shown that in mice betatrophin significantly improves beta cell function and glucose tolerance. This is the first study on betatrophin in which pregnant women were observed during all trimesters and in postpartum period to evaluate its role in increasing insulin resistance and physiological proliferation of beta cells.

Materials and methods: We examined 80 healthy pregnant women in each trimester (T1, T2, T3). Forty-five of them were additionally examined at 3MPP. We also examined 30 non-pregnant women of reproductive age without obesity as the control group. We measured betatrophin levels (ELISA), glucose (enzymatic method with hexokinase), insulin (immunoradiometric method), C-peptide (enzyme amplified sensitivity immunoassay), HbA1c (HPLC). We calculated HOMA-IR and HOMA%β. The oral glucose tolerance test was performed in T2 and 3MPP.

Results: In T1 betatrophin level was highest and it significantly differed from T2 and T3 (1.84±1.51 ng/ml vs 1.46±1.25 ng/ml, P<0.05; 1.84±1.51 ng/ml vs 1.23±1.29 ng/ml, P<0.01; respectively). In T3 median value of betatrophin reached lowest level and we observed significant difference with 3MPP (1.23±1.29 ng/ml vs 1.49±1.54 ng/ml, P<0.01). In 3MPP betatrophin level was similar to the control group (1.49±1.54 vs 1.47±1.78). HOMA-IR and HOMA%β increased during the course of gestation. It reached a peak in T3 (2.3±1.06; 227.7±140.8, respectively) and returned to the healthy control values (1.53±1.3; 88.86±68, respectively) at 3MPP (1.35±0.6; 92.5±37.3, respectively). Data are shown as median and interquartile range.

Conclusions: Decreasing betatrophin concentration during pregnancy despite the physiological proliferation of beta cells throughout gestation can suggest that betatrophin plays an insignificant role in the expansion of beta cell mass and insulin resistant during pregnancy. Further studies are needed to establish what factors impact on betatrophin levels during each trimester of pregnancy.