INS and polycystic ovary syndrome: Importantly, after metformin treatment, circulating betatrophin levels in PCOS women were significantly decreased following increasing insulin sensitivity (from 0.54 ± 0.13 to 0.35 ± 0.12μg/L at post-treatment 3 months, and finally to 0.31 ± 0.10 μg/L at post-treatment 6 months, vs. baseline, both P <0.01; Figure 1F).