A STUDY WITH RADIOACTIVE PHOSPHORUS OF THE PERMEABILITY OF THE RAT PLACENTA TO PHOSPHOLIPID

Abstract

A comparison was made of the P32 activity of the phospholipid extracted from 2 groups of fetal rats, the mothers of the one group had been injected with inorganic P32, and the mothers of the 2d had been injected with tagged phospholipid. Extractions were made in both groups 2 hrs. following the inj. of the mothers. A ratio of the activity recovered per g. of fetal phospholipid to the activity injected per g. of adult was found for each animal. Significantly higher ratios obtained when inorganic P32 was injected. In rats injected with inorganic P32 and allowed to go 1 hr. before extraction of the fetal phospholipid there existed a higher ratio than was the case when tagged phospholipid was injected and allowed to go 2 hrs. before extraction. No trends in transfer at different gestation ages were seen. Placental transfer of the phospholipid molecule as such in the rat is evidently a very slow process.