Urinary melatonin, LH, oestradiol, progesterone excretion during the menstrual cycle or in women taking oral contraceptives.

Nocturnal urinary excretion of melatonin, LH, progesterone and oestradiol was measured by radioimmunoassay in nine normal women during a complete cycle. In addition, these hormonal excretions were studied in two women taking an oral contraceptive. A high within-subject coefficient of variation was observed for melatonin excretion in the two groups. In the nine normal cycling women, melatonin excretion was not decreased at the time of ovulation, but was significantly increased during the luteal phase compared with that of the follicular phase (P less than 0.01). These data are consistent with a positive relationship between melatonin and progesterone during the luteal phase. In the two women under an oral contraceptive, melatonin excretion was found within the same range as for the other nine. The results are discussed in terms of pineal investigation in human.