[Localization of B-glycuronidase activity in homogenates of placentas at different gestational ages and in different subcellular organelles].

The B-glycuronidase activity has been dosed by the methodic of Fishman using phenolphtaleingly curonide, in homogenates of placentas from pregnant women at different gestational ages. The presence of the enzyme has also been investigated in various cellular organelles (nuclei, lysosonomes and past-lysosomal fraction) obtained from placenta homogenates by Contractor and Shan e's method. The enzymatic activity, already present in the secondary villus (6.35 mg/g of dry tissue--4th weeks of gestation) increases between the first and second month of gestation, when the tertiary villus replaces the secondary one (9 mg dry tissue-12th weeks of gestation) Thenceforward (from the 2nd to the 9th month of pregnancy) the enzymatic activity remains constant. Around 30% of the B-glycuronidase activity is present in the lysomes, while 40-45% is localized in the microsomes formed by the lipoproteic membranes of the endoplasmic reticulum. The remaining 20% was found in the nuclei. Such activity is not due to the nucleus itself, but to membranous lipaproateic fractions of the reticulum which, for the centrifugation, precipitate absorbed to the nuclear membranes.