A, Treprostinil (300 ng/kg/min) and metformin (300 mg/kg) were given through osmotic minipumps and drinking water, respectively, for 14 weeks to 8-week old SU5416/obese ZSF1 rats (Ob-Su). Body weights (B), fasting blood glucose levels (C), HbA1c levels (D), glucose tolerant abilities (E) and right ventricular systolic pressures (RVSP, G) were measured. F, Representative images and percentage of milky, slightly opaque and transparent plasma samples in different groups. Data are mean ± SEM; n = 5–8 rats/group; *P < 0.05, ***P < 0.001 and ****P < 0.0001 vs. ln; #P < 0.05, ##P < 0.01, ###P < 0.001 and ####P < 0.0001 vs. Ob-Su.