Phosphate (P 32 ) Exchange in Brain Phospholipids in vivo and in vitro . ∗ †

Abstract

Summary

In vitro, the specific activity of the phospholipid phosphate reaches a maximum within 20 minutes after the start of incubation, while in vivo the specific activity of this fraction rises continuously for at least 20 hours after the intraperitoneal administration of P³². When the lipid extract is divided into crude fractions, it is observed in in vitro experiments that the specific activities of these fractions are markedly dissimilar. Conversely, the specific activities of these fractions are approximately the same when obtained from the brains of rats that had been injected with P³² 20 hours previously. some of the factors involved in these findings have standard microbiological method.