No abstract

The extent of lipid peroxidation and the levels of its antioxidants such as superoxide dismutase (SOD), catalase and glutathione peroxidase (GSH-Px) were determined on lung tissues of the fetal, newborn and adult rat. Lipid peroxide formation was slight in the fetal period but augmented after birth reaching a peak at about 10 days after birth. The peroxide concentration then gradually declined with development and the adult level was found comparable to the fetal level. In the examination of the developmental defensive mechanism on the basis of assays for the aforementioned antioxidant enzymes in lung tissue, the SOD activity was low in fetuses reaching approximately 90% of the adult level at 10 days of life. Catalase was extremely low in concentration at all times, and age-related variations could not be definitely obtained. GSH-Px was also measured low in the fetal period and during 20 days after birth, but a subsequent gradual rise resulted in threefold greater activity in adults than in fetuses.

Superoxide dismutase (SOD) activity was measured in the maternal and cord blood by the modified method of Beauchamp and Fridovich, using a carbonate-buffered (pH 10.2) xanthine-xanthine oxidase system. No great differences between maternal and cord blood in erythrocyte SOD levels were observed, with the exception of whole blood; namely, washed RBC showed a SOD activity of a fairly high level, which was comparable to the activities of crude SOD, but showed no difference between them. In contrast, the SOD activity in the maternal whole blood was significantly lower than that in the cord blood. In measuring SOD activity, the serum factor has a great effect, and serum contains a substance that inhibits NBT reduction. Only one band of SOD has been detected which shows identical Rf values both in maternal and cord blood by polyacrylamide-gel electrophoresis.