[The effect of repeated fasting on the ratio of individual fatty acids in the brain and blood of rats of various ages].

In locally bred, 5-day old and full grown rats, the authors conducted experiments where they investigated the influence of repeated fasting (3 X 18 hours food deprivation on three consecutive days) on a wide spectrum of fatty acids in the cerebral cortex, medulla oblongata and serum. The fatty acids were assessed as methyl esters by gas chromatography, as described in previous work (1, 13, 14, 17). In 5-day old rats after repeated fasting an evident decline in the ratio of saturated fatty acids in serum was recorded; at the same time the ratio of arachidonic acid increased markedly and in the cerebral cortex there was a significant drop of the palmitic acid participation. In adult rats 16 statistically significant changes took place (treble as compared with the 5-day old rats). The large number of significant changes pertained to 18 carbon fatty acid (a rise in all instances in the brain; the ratio of 18:3n-6 in plasma declined significantly). In the serum of adult rats the ratio of arachidonic acid increased also. The authors discuss possible reasons of the described changes.