Accumulation of Brain Tryptophan in Rats after Administering Various Fats or Fatty Acids

The intragastric administration of various kinds of fat (corn oil, lard, safflower oil, perilla oil, and fish oil) or fatty acids (oleic acid, linoleic acid, linolenic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA)) caused a significant increase in brain tryptophan (especially with fish oil or DHA), and also in serum insulin. However, at 2 h after administering the fats or fatty acids, brain serotonin was not increased in accordance with the increase of brain tryptophan. As a result of determining the time-dependent changes in brain 5-hydroxyindoles, brain serotonin and 5-HIAA gradually increased, and showed significant increases at 6 hand 4 h after the administration of fish oil, respectively. These results suggest that there was a fairly long time-lag for the changes in brain 5-hydroxyindoles to appear after being induced by the administration of fats or fatty acids.