A serine/alanine polymorphism in the nucleotide‐binding fold‐2 of the sulphonylurea receptor‐1 (S1369A) is associated with enhanced glucose‐induced insulin secretion during pregnancy

The sulphonylurea receptor‐1 (SUR‐1) regulates glucose‐induced insulin secretion by controlling K+‐ATP channel activity of the pancreatic β‐cell membrane. In this study, we investigated the putative role of a T/G‐polymorphism (exon 33, codon 1369; S1369A) in the adenosine diphosphate‐sensing nucleotide‐binding fold‐2 (NBF‐2) of the SUR‐1 on glucose‐induced insulin secretion during an oral glucose tolerance test in pregnant women (PW; n=182). Compared to PW with the T/T genotype, statistically significant elevated C‐peptide concentrations were found 60 min after glucose intake in PW with the T/G and G/G genotype (T/T 9.0±0.4 ng/ml vs T/G 10.8±0.4 ng/ml or G/G 10.8±0.7 ng/ml, p=0.01). Furthermore, compared to PW with T/T genotype the ΔC‐peptide (60/0 min) was significantly enhanced in PW with T/G or G/G genotype (T/T 6.7±0.3 vs T/G 8.9±0.4 or G/G 8.9±0.7, p=0.0009). A significant correlation of C‐peptide concentrations with blood glucose (BG) 60 min after glucose intake was only found in PW with the T/T genotype (r=0.6, p