EFFECTS OF MATURATION ON THE PHOSPHOLIPID AND PHOSPHOLIPID FATTY-ACIDCOMPOSITIONS IN PRIMARY RAT CORTICAL ASTROCYTE CELL-CULTURES

Phospholipid and phospholipid fatty acid compositional changes were st udied in rat cortical astrocytes during dibutyryl cyclic adenosine mon ophosphate (dBcAMP, 0.25 mM) treatment starting after 14 days in cultu re (DIC). lifter 15 DIC, ethanolamine- and choline glycerophospholipid levels were increased 1.2- and 1.3-fold, respectively ir. treated com pared to control cells. However, after 21 and 28 DIC, these levels wer e not significantly different between groups. Roth groups had an incre ase in phosphatidylserine levels with increasing time in culture. Simi larly, ethanolamine plasmalogen levels were transiently elevated after 21 DIC, but returned to previous levels after 28 DIC. The phospholipi d fatty acid compositions for the acid stable and labile ethanolamine- and choline glycerophospholipids indicated that in dBcAMP treated cell s, 20:4 n-6 and 22:6 n-3 proportions were elevated with increasing tim e in culture relative to control cells. As 20:4 n-6 proportions increa sed, there was a concomitant decrease in 20:3 n-9 proportions, suggest ing an up regulation of n-6 series elongation and desaturation. In con trast, in control cells, the 20:4 n-6 proportions decreased with a cor responding increase in the 20:3 n-9 proportions. Thus, in treated cell s, the cellular phospholipid fatty acid composition was dramatically d ifferent than control cells, suggesting that dBcAMP treatment may act to increase fatty acid elongation and desaturation.