Melatonin: Identification of Sites of Antigonadal Action in Mouse Brain

Abstract
Long-term implants releasing a small quantity of melatonin (45 nanograms per day) were used to determine the brain sites of the hormone's antigonadal action in a photoperiodic species, the white-footed mouse ( Peromyscus leucopus ). Implants in the medial preoptic and supra- and retrochiasmatic areas elicited complete gonadal regression after 7 weeks. Implants in other brain regions had little effect on the animals' reproductive state.