INS and polycystic ovary syndrome: Following treatment with TGFβ1 (1 ng/ml and 5 ng/ml) with and without insulin, there was an increase in pSMAD3/SMAD3 in myotubes from both healthy women and women with PCOS (1 ng/ml ± insulin: P < 0.001, 5 ng/ml ± insulin: P < 0.001, Figure 1B).