Increased LH pulse frequency, an elevated serum LH/FSH ratio, and greater pituitary LH responsiveness to GnRH in women with PCOS (31) are all likely due to an increased frequency of pulsatile GnRH secretion from neurons in the hypothalamus into the anterior pituitary portal venous drainage (3, 31, 193). This evidence concerns the gene PLOD1 and polycystic ovary syndrome.