The present report is the first in a projected series of investigations on biogenic amine-synthesizing and -degrading enzymes in trophoblast. The work is being undertaken to gain information relating to two questions. First, do the placental enzymes which degrade biogenic amines and related compounds provide an important biochemical barrier which protects the fetus against undesirable stimulation by physiological and pharmacological compounds in the maternal circulation? Secondly, do critical changes in biogenic amine metabolism in the placenta precede or accompany parturition, and might they be involved in the actual mechanism underlying the initiation of parturition?
Catechol-O-methyltransferase (COMT, E.C.220.127.116.11) is an enzyme which inactivates certain catecholamines and O-methylates 2-hydroxyoestradiol-17 β (Ball, Knuppen, Haupt & Breuer, 1971); it has been purified 66-fold from human placenta (Gugler, Knuppen & Breuer, 1970).