PLOD1 and polycystic ovary syndrome: During puberty, the hypothalamic-pituitary-ovarian axis is matured and the circulating LH levels are subsequently increased [19]. In particular, adolescents with PCOS show increased frequency and amplitude of gonadotropin-releasing hormone (GnRH) and LH pulses, as well as an increased ratio of LH to follicle-stimulating hormone (FSH) [20].