Periovulatory beta-endorphin levels in premenstrual syndrome.

Abstract

To determine whether changes in peripheral beta-endorphin levels during the periovulatory phase are associated with symptoms of premenstrual syndrome (PMS). Twenty-one PMS patients and ten controls were studied. All were in general good health and had no history of psychiatric disorders. They were between 21-44 years of age, had had regular menses for at least six previous cycles, and were carefully selected by charting the Visual Linear Analogue Scale and basal body temperature daily for 1 month. After an overnight fast, the subjects had blood drawn between 8:00 and 10:00 AM daily for 8 days, starting on the tenth day of the menstrual cycle, for one cycle. Beta-endorphin and LH were measured by radioimmunoassay. The day of the LH peak was defined as day LH 0. The beta-endorphin levels were expressed as the number of days before or after the LH surge. Beta-endorphin levels throughout the periovulatory phase were lower in PMS patients than in controls, and the differences were more remarkable on LH days 0 and 4. Our data suggest that an aberration of normal changes in beta-endorphin activity in PMS patients may occur around the time of ovulation.