Melatonin and the pituitary response to GnRH in prepubertal and adult ewes.

GnRH-induced LH-release was studied in female lambs from 5 weeks of age until puberty and in adult anoestrous ewes. In pre-pubertal animals LH was released rapidly after GnRH treatment but after puberty the responses became slower and more sustained although the peak concentration did not change. In neither pre-pubertal nor adult sheep did prior treatment with melatonin influence LH release after GnRH treatment.