PRL and hyperprolactinemia: Prolactin excess (hyperprolactinemia) may lead to hypogonadism, galactorrhea, etc. In addition to physiological causes such as ovulation and pregnancy, hyperprolactinemia may also be caused by prolactin-secreting pituitary adenoma, liver cirrhosis, polycystic ovarian syndrome, and stress, which may be related to oxidative stress [35].