Microcystin (-LR) affects hormones level of male mice by damaging hypothalamic-pituitary system

► Intraperitoneal injected MC-LR affected male mice serum hormone level. ► MC-LR induced a decrease in GnRH expression, depend on dose and duration. ► MC-LR increased and then decreased the secretion of FSH, LH and testosterone. ► MC-LR was not able to enter Leydig cells and had no cytotoxicity on Leydig cells. ► MC-LR might significant damage both hypothalamus and pituitary.