“In the follicular phase, melatonin administration enhanced the LH and FSH responses to all three GnRH stimuli, whereas in the luteal phase, melatonin administration was ineffective.”
“In this study we investigated whether an increased pituitary response to GnRH is involved in the stimulatory effect of melatonin.”
“The present data indicate that an enhancing effect of melatonin on the LH and FSH responses to submaximal GnRH stimuli is evident in the follicular, but not the luteal, phase of the menstrual cycle and infer an endocrine window for the effect of melatonin on gonadotropin secretion.”