RELATIONSHIP BETWEEN MONOAMINE OXIDASE ACTIVITY AND SEX HORMONE CONCENTRATION IN HUMAN BLOOD PLASMA

MAO activity during the luteal phase was positively correlated with P and with T, which indicates that the greater the progesterone:estradiol ratio the higher the activity of MAO.

Abstract

Summary. The activity of MAO and the concentrations of various sex hormones were determined in blood plasma from healthy men and women and from pregnant women in the third trimester. The enzyme activity is greater in plasma from men than from women at the time of ovulation, but not during the luteal phase. The activity is unchanged during pregnancy. Plasma MAO activity is significantly negatively correlated with testosterone concentration in men and with oestradiol concentration in women. During the luteal phase, the activity is positively correlated with the progesterone : oestradiol ratio of plasma. Enzyme activity is significantly reduced in plasma from women taking oral contraceptive preparations, but not from women receiving depot MPA as a contraceptive. Oral doses of MPA or hydrocortisone had no significant effect on plasma MAO activity in men.