Abstract: The present invention provides a method for inducing an estrous cycle in a female mammal, including humans and non-human (lower) mammals with a monoamine oxidase inhibitor such as deprenyl wherein the estrous cycle of the female mammal had been inhibited by the regular treatment for a period of time whih an estrous cycle-inhibiting composition, which has been discontinued leaving the female mammal unable to ovulate, prior to impregnating with sperm. In particular, the present invention provides a method for inducing heat in a canine, particularly a retired racing greyhound to induce pregnancy. Thus, the object of the present invention is to provide a method that restores reproduction in domestic animals, in comparison animals, in captive wild animals, and in human females.