The pattern of melatonin in amenorrheic women affected by sterility.

The authors analyzed the pattern of melatonin in the menstrual cycles of six amenorrheic women affected by sterility. Only in one ovulatory cycle did melatonin respect its typical secretory behavior, i.e., nadir in the preovulatory period followed by an increase in the luteal phase, even though melatonin values were higher than normal over the entire cycle. The melatonin pattern in the five cycles showing no evidence of follicular recruitment nor regular formation of a main follicle was different from that seen in an ovulatory cycle. The authors support the concept of a correlation between the pineal gland and pituitary gland and hypothalamus, also because previous studies have demonstrated the presence of melatonin in follicular and peritoneal fluid. They conclude that there is a role for melatonin in the regulation of the menstrual cycle even though they have not as yet uncovered the specific mechanism.