In many mammals, the duration of the nocturnal melatonin elevation regulates seasonal changes
in reproductive hormones such as luteinizing hormone (LH). Melatonin's effects on human
reproductive endocrinology are uncertain. It is thought that the same hypothalamic pulse
generator may both trigger the pulsatile release of GnRH and LH and also cause hot flashes.
Thus, if melatonin suppressed this pulse generator in postmenopausal women, it might moderate
hot flashes. This clinical trial tested the hypothesis that melatonin could suppress LH and
relieve hot flashes.