Membrane progestin receptor alpha mediates progestin-induced sperm hypermotility and increased fertilization success in southern flounder (Paralichthys lethostigma).

•Progestins induce flounder sperm hypermotility through mPRα.•Progestins increase motility and fertility in sperm with high mPRα expression.•LHRHa treatment increases flounder sperm mPRα expression, motility and fertility.•Progestins increase flounder sperm cAMP levels through membrane adenylyl cyclase.