GPER1 and Insulin resistance: Moreover, the GPER1-HKO female mice developed more severe glucose homeostasis impairment and insulin resistance, as indicated by the elevation of fasting blood glucose levels, insulin levels, and HOMA-IR values, the reduction of glycogen levels, and more impaired insulin signaling pathway, as well as intraperitoneal GTT and ITT assays than that of the GPER1-Flox control female mice (Fig. S6, C–I).