In addition to hormonally-induced mouse models of PCOS; transgenic (estrogen receptor knockout; aromatase knockout), diet-induced or chemically-induced mouse models of PCOS (for instance, by D-galactose, monosodium L-glutamate, bisphenol A or tributyltin) have also been described [31, 42, 90, 114, 126]. Here, ESR1 is linked to polycystic ovary syndrome.