Glycerophospholipids and acyl group changes in rat brain capillary endothelial cell fraction and the liver during development.

The glycerophospholipid (GPL) content and the acyl group compositions of the ethanolamine and choline glycerophospholipids (EGP, CGP) of the isolated brain capillary cell fractions of the developing rat have been determined. The proportion of EGP/GPL increases during development, whilst CGP/GPL declines: consequently EGP/CGP increases with age. The acyl group compositions of the plasmenylethanolamine (P-GPE) and the diacyl glycerophosphocholine (D-GPC) also change during development, the proportions of saturated fatty acids (SFAs) declining and n-6 groups rising. The rates of accumulation of individual acyl groups of EGP and CGP are highest between the ages of 15 and 20 days; particularly evident is the increase in the medium chain SFAs: 16:0 and 18:0, the monoene 18:1n-9 (oleic acid) and the major-occurring polyunsaturated fatty acid, arachidonic acid, in these GPLs. These changes are compared with those of the liver where the proportion of EGP/CGP remains constant and the acyl group compositions are relatively unchanged during development. Consequently, the rates of accumulation of individual acyl groups of EGP and CGP in liver remain constant or rise slightly during this age period. These results are compared with existing accounts of the desaturation capabilities of brain and liver with age.