Any of several hormones, secreted by the mammalian anterior pituitary gland, that stimulate reproductive activity of the testes or ovaries (the gonads). Pituitary gonadotrophins include follicle-stimulating hormone and luteinizing hormone. Chorionic gonadotrophin is a hormone produced by the placenta of higher mammals that maintains the corpus luteum. The presence of large amounts of human chorionic gonadotrophin (hCG) in the urine of women is an indication of pregnancy.