The metabolism of phospholipids in mouse brain slices

Abstract

1. Slices of mouse brain grey matter were incubated with [(32)P]phosphate and [1-(14)C]acetate. Doubly labelled phospholipids were extracted from subcellular fractions prepared from the slices in a mixture of metabolic inhibitors, under conditions where there was negligible change in radioactive labelling during the preparation. Two tissue fractions were studied in detail; one contained a high proportion of mitochondria and the other was mainly microsomal. 2. In all tissue fractions the highest incorporations of both [(32)P]phosphate and [1-(14)C]acetate occurred into phosphatidylcholine. 3. After incubation for 1hr., the (32)P/(14)C ratios for phosphatidylcholine, phosphatidylethanolamine and phosphatidic acid in the mitochondrial fraction were similar to those in the microsomal fraction. 4. The (32)P/(14)C ratios were similar in phosphatidylcholine and phosphatidylethanolamine and much lower than those in phosphatidic acid and phosphatidylinositol.

The acyl and Alk‐1‐enyl groups of the major phosphoglycerides from ox brain myelin and mouse brain microsomal, mitochondrial and myelin fractions

“…Fortunately, the G.Y. SUN AND HORROCK~q extent of phospholipid exchange in the brain is quite low under the conditions of subcellular fractionation (32). Additional analyses of specific types of brain cells are required before the unique acyl and alk-l-enyl group compositions and the high content of alk-l-enyl acyl GPE of myelin can be ascribed to an oligodendroglial cell specificity or to a myelin membrance specificity.…”

The turnover of phosphatidyl choline in rat cerebral cortex membranes in vivo

“…Co.) which was chromatographed on each plate. The area of the plate corresponding to rat brain P C was scraped off and extracted 3 times with 3 ml of chloroform: methanol :water (49 : 49 : 2 by vol) (Clayton and Rowe, 1966). The combined extracts were evaporated to dryness under reduced pressure and dissolved in 2 ml of methanol.…”

THE INCORPORATION OF [1‐14C]ACETATE INTO UNESTERIFIED FATTY ACIDS IN RAT CEREBRAL CORTEX IN VIVO

“…The washed tissue pellet was extracted with 2 0~0 1 of ch1oroform:methanol (2: I, v/v) (FOLCH-PI et al, 1957). The total lipid extract was washed once with 0.2 vol of 0.1 M-sodium acetate and twice with 'thcoretical upper phase'(FoLcH-Pi eta/., 1957) containing 0 5 M-sodium acetate (CLAYTON & ROWE. 1966).…”