October 1974

Human Platelet Monoamine Oxidase Changes During the Menstrual Cycle

Author Affiliations

From the Section on Twin and Sibling Studies, Adult Psychiatry Branch (Drs. Belmaker and Wyatt), and the Laboratory of Clinical Science (Dr. Murphy), National Institute of Mental Health; and the Reproduction Research Branch, National Institute of Child Health and Human Development (Dr. Loriaux), Bethesda, Md.

Arch Gen Psychiatry. 1974;31(4):553-556. doi:10.1001/archpsyc.1974.01760160093019

Monoamine oxidase (MAO) is a major enzyme in the catabolism of brain biogenic amines. Platelet MAO activity has been shown to be largely under genetic control. Animal studies, however, have suggested that endocrine factors may contribute to the nongenetic component of the variance in MAO activity between individuals.

To evaluate the possible effects of sex steroid changes on platelet MAO activity, blood samples for platelet MAO assay and plasma estradiol and progesterone levels were obtained twice weekly from 13 women. Peak MAO activity occurred during the ovulatory interval, and a nadir occurred 5 to 11 days later. The mean effect of the menstrual cycle-related variation was 23%. No statistically significant relationship was observed between platelet MAO activity and a global scale of menstrual mood variation.