Influence of progesterone on serotonin metabolism: a possible causal factor for mood changes

Abstract

(1) Premenstrual and postpartum feelings of irritability, tension and depression are rather common, and are associated with a decline in the secretion of female sex steroids. (2) In a study on the sensitivity to experimental stress in the premenstrual phase of normal subjects, there were generally higher reactions to stress, as measured by average pulse rate, 1 day before menstruation than 8 days before menstruation when serum progesterone is at its peak. (3) It was not possible, however, to establish a clear relationship between progesterone levels and progestagen treatment. (4) Experiments with ovariectomized rats did not show clear evidence that progesterone exerted an effect on brain noradrenaline (NA), but did increase serotonin (5-HT) turnover. (5) An effect of progesterone could be shown in stress-altered 5-HT metabolism. (6) When footshock was administered to ovariectomized rats pretreated with progesterone, there were generally higher 5-HT and 5-hydroxyindolacetic acid (5-HIAA) concentrations than in stressed controls. (7) Footshock also raised endogenous progesterone levels, but there did not seem to be a relationship with changes in 5-HT metabolism.