Effects of dietary nucleotides on lipid metabolism and learning ability of rats.

To investigate the effects of dietary nucleotides on lipid metabolism and learning ability, male Sprague-Dawley rats were fed with a nucleotides-supplemented diet or a nucleotides-free diet for 5 weeks. The content of nucleotides in the diet was 1.0% and their composition resembled that in human milk. The content of phosphatidylcholine (PC) and the ratio of PC to phosphatidylethanolamine (PE) in the cerebral cortex of rats fed the nucleotides-supplemented diet were significantly higher than that of rats fed the nucleotides-free diet. However, there was no difference in the content of PC and the ratio of PC to PE in the liver between the two groups. The levels of docosahexaenoic acid (C22:6n-3) and arachidonic acid (C20:4n-6) in the cerebral PC fraction were higher in rats fed the nucleotides-supplemented diet. The learning ability of rats fed the nucleotides-supplemented diet, which was evaluated by the water-filled multiple T-maze test and passive avoidance test, was superior to the of rats fed the nucleotides-free diet. The results presented here suggest that dietary nucleotides may influence lipid metabolism of the cerebral cortex and contribute to the rise in learning ability of rats.