GIRKO mice have reduced overall fat mass despite modest differences in adipocyte morphology.A, epididymal white adipose tissue (EWAT) mass as a percent of body weight (bw) after 14 weeks of HFD exposure. B, representative hematoxylin and eosin-stained images of EWAT in control and GIRKO mice. Scale bar is 500 μm. C, comparison of the percent of small and large adipocytes in EWAT. The median adipocyte size of Control EWAT was used as a cutoff to determine small or large adipocytes and was set to 324 μm (2). (n = 5 Control, 7 GIRKO). D, average area of adipocytes in EWAT. (n = 5 Control, 7 GIRKO). E, serum leptin concentration in NCD and HFD cohorts. (n = 8 Control-NCD, 7 GIRKO-NCD, 8 Control-HFD, and 9 GIRKO-HFD). F, correlation between serum leptin concentration to EWAT mass. n = 8 Control, 9 GIRKO. G, mRNA expression of adipocyte marker genes. Data shown are Mean ± SEM. Statistical comparisons in panels A, D, and G were performed using student's t test Statistics in panels C and E are from two-way ANOVA and Sidak post-hoc test. (∗) indicates p < 0.05, (∗∗) indicates p < 0.01, (∗∗∗) indicates p < 0.001.