Estrogen and progesterone secretion in monkeys (Macaca fascicularis) following melatonin or Altschule's pineal extrac.

Large doses (30MG) of melatonin given weekly to crab-eating monkeys throughout five menstrual cycles did not change the pattern of estrogen and progesterone secretion during the period of injection or in the two succeeding cycles. Altschule's pineal extract, unlike melatonin, had no effect on estrogen or progesterone secretion during the period of injection or in the two succeeding cycles, when it was given daily between days 7 and 17 of the menstrual cycle.