PIK3R1 and gestational diabetes: Overall, relative expression values were similar between VAT and SAT for IRS1 and PI3KCA. In VAT, mRNA gene expression of PI3KR1 (p85) was significantly reduced in women with GDM (GDM: 1192 ± 49 vs. NGT: 1543.6 ± 110, P = 0.012).