(A–G) Effects of Pioglitazone (PIO) treatment on TG and HDL-c (A), C-peptide and proinsulin levels (B), glucose excursion during IVGTT (C), insulin excursion during IVGTT (D), HOMA-IR (E), Δinsulin/Δglucose (at 10 min) during IVGTT (F), area under the insulin curve (AUCinsulin) (0 – 10 min) (G). Note that the effects of PIO were largely reversible. (H) & (I) PIO treatment normalized the FMD duration (H) and amplitude (I) in the MetS monkeys. Note that the effect was persistent after a 6-week washout. Data are expressed as mean ± SEM (n = 12 monkeys). PIO vs baseline (BL): * p<0.05, ** p<0.01, PIO vs washout: # p<0.05, ## p<0.01 (paired T-test).