Placental insufficiency investigated by enzyme histochemistry

ABSTRACT

The enzyme histochemistry of 92 placentae representing various normal and abnormal pregnancies at different stages of gestation was studied. Alkaline phosphatase and glucose-6-phosphatase showed a rising concentration in the trophoblast with advancing pregnancy. Acid phospatase within the trophoblast showed an apparent tendency to decrease in amount in late pregnancy. Lactate dehydrogenase, malate dehydrogenase, alpha-glycero-phosphate dehydrogenase and glucose-6-phosphate dehydrogenase were present in the trophoblast throughout pregnancy without any apparent change in concentration. Succinate dehydrogenase could not be found in the trophoblast at any time, occurring only in the decidua underlying the placental bed. Leucine amino-peptidase showed a patchy distribution throughout the connective tissue stroma of the chorionic villi and within the walls of the larger blood vessels. It was suggested that a high concentration of alkaline phosphatase and glucose-6 phosphatase associated with a low concentration of acid phosphatase constituted the histochemical parameters of placental insufficiency (AU)