This is supported by data demonstrating that PCOS women require higher amounts of progesterone to suppress LH secretion compared to levels of non-PCOS women (Pastor et al., 1998) and through evidence that long-term treatment with an androgen antagonist, flutamide, restores normal progesterone sensitivity in women with PCOS (Eagleson et al., 2000). This evidence concerns the gene PLOD1 and polycystic ovary syndrome.