Plasma met-enkephalin and catecholamine changes during the menstrual cycle and pain episode in menstrual migraine.

In order to explore opioid, sympathetic and hormonal parameters, we evaluated plasma met-enkephalin (ME), catecholamines (CA), estradiol (E2) and progesterone (P) in different phases of the menstrual cycle and during menstrual crisis in women suffering from menstrual migraine (MM) and in controls. No differences in P and E2 were found between controls and patients. We observed an increase in plasma ME and a decrease in plasma free norepinephrine (NE) levels on day 22 in MM group and an increase in plasma ME, free NE and total epinephrine (E) during pain. Our data, although obtained in a small number of patients, show clear modifications in plasma ME and in the sympathoadrenal function, not only during pain but also in the mid luteal phase.