Effect of oestrogens and progesterone on the metabolic inactivation of noradrenaline in the human placenta.
The enzymatic inactivation of noradrenaline was investigated in 25 fresh human placentae in vitro. Oxidative deamination by monoamine oxidase (MAO) was greater than enzymic O-methylation by catechol-O-methyltransferase (COMT). The addition of oestriol (E3) or progesterone to the organ bath significantly decreased (P less than 0.001) the activity of placental MAO. Oestrone (E1) and oestradiol (E2) showed no inhibitory effect. In addition, E3 significantly inhibited the activity of COMT (P less than 0.001), whereas oestrone and oestradiol had no effect on COMT activity. COMT was also inhibited by progesterone (P less than 0.05). The decrease in enzymic inactivation of noradrenaline caused by oestriol and progesterone suggests an activated adrenoceptor function.
Saarikoski
S
S
Department of Obstetrics and Gynaecology, University Central Hospital, Kuopio, Finland.
D002394:Catechol O-Methyltransferase / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology; D004964:Estriol / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D004970:Estrone / Q000494:pharmacology; D005260:Female; D006801:Humans; D008995:Monoamine Oxidase / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism*; D010920:Placenta / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D011247:Pregnancy; D011374:Progesterone / Q000494:pharmacology*
D004967:Estrogens; D004970:Estrone; D011374:Progesterone; D004958:Estradiol; D008995:Monoamine Oxidase; D002394:Catechol O-Methyltransferase; D004964:Estriol; D009638:Norepinephrine