Investigations on the activity of the histaminase in normal and toxaemic pregnancy

By means of a colorimetric method the activity of the histaminase in the sera and placentae of pregnant $$ was detd. by using cadaverine and histamine as substrates in parallel tests. Whereas the histaminase reaction was negative in the serum of non-pregnant women it was positive without exception in normal pregnancy serum irrespective of the substrate used. The activity of the histaminase in the serum was diminished in mild cases of pre-eclamptic toxemia and only a trace of activity or a negative enzymic reaction was obtained in cases of hyperemesis gravidarum, in severe cases of pre-eclamptic toxemia and in eclampsia. The results obtained in investigations of 45 placentae suggest a possible correlation of the amt. of the histaminase in the placentae with the character of the labor, the activity of the histaminase in the placenta being inversely proportional to the uterine efficiency. The results obtained render doubtful Zeller''s claim that the histaminase and diaminoxidase are identical.