Effect of nicotinic acid on myelin lipids in brain of developing rat.

Weanling rats (weaned 12 days after birth) were fed on nicotinic acid-deficient and on nicotinic acid-supplemented diet separately for 7 and 21 days. The yield of myelin in the brain of rat fed on the nicotinic acid-deficient diet was lower than that in the case of receipt of the nicotinic acid-supplemented diet at 19, 26 and 33 days of age. Despite the changing yield of myelin, the proportion of protein and total lipids, and the percentage composition of lipid were not changed between the groups fed on the nicotinic acid-deficient and the nicotinic acid-supplemented diet. Moreover, the ratio of long chain fatty acid (C20-23/C14-18) was markedly decreased in the nicotinic acid-deficient rats. These findings imply that nicotinic acid may play an important role in myelination associated with the synthesis of cerebrosides which contain high levels of long chain fatty acid.