YWHAZ and polycystic ovary syndrome: In agreement with the findings of the present study, PPIA, HPRT1, and/or YWHAZ have been validated as the most stable RGs in HPG-axis tissues including the brain, pituitary, ovary, and testis in songbirds [26], testosterone-influenced hypothalamus and kidney of rats [27], normal and adenoma tissues of pituitary gland from dogs and mice [28], and human polycystic ovarian syndrome [29].