Effect of pinealectomy on fatty acid composition of rat brain myelin

To determine whether the previously demonstrated decrease in rat brian myelin after pinealectomy is associated with an abnormality in myelin composition, 92 rat pups were subjected either to pinealectomy or sham-pinealectomy at 4 days of age. These animals, reared in diurnal lighting, were killed at 40 days of age, and their brains were individually subjected to myelin fatty acid analysis. In both sexes, all the significant differences, as determined by multivariate analysis of variance, were found in the long chain fatty acids (chain lengths of 16 carbons or more). It was also observed that in 5 of 6 instances in which a significant difference appeared in both sexes for the same fatty acid, the mean quantity of each of these fatty acids in the pinealectomized animals was neither consistently higher nor lower than the comparable sham-operated mean. These results suggest that neonatal pinealectomy in the rat alters the fatty acid composition of brain myelin.