Reduced atrial natriuretic peptide concentrations in premenstrual syndrome.

Atrial natriuretic peptide (ANP) concentrations were determined by radioimmunoassay technique in 23 women, 11 women with premenstrual syndrome (PMS) and 12 comparable asymptomatic women. The asymptomatic women showed no change in ANP concentration during the menstrual cycle. In the PMS group ANP levels showed a significant fall in the midluteal phase compared to levels in the follicular phase. Throughout the cycle ANP concentrations were lower in the PMS group than in the comparison group. This difference was statistically significant in the early, mid and late luteal phases of the cycle. The lower ANP concentration in the PMS group in the luteal phases may indicate either a lower plasma volume or a decrease in the total body sodium content or both. These findings are contrary to those expected.