Effects of vitamin B12 deficiency on lipid metabolism of the rat liver and nervous system.

Abstract

1. Rats bred from vitamin B12-depleted dams were fed on a vitamin B12-deficient diet for 12-15 months and developed a severe vitamin B12 deficiency, as judged from methylmalonic acid excretion and tissue vitamin B12 levels at slaughter. Control rats were supplemented with vitamin B12 in the drinking-water. 2. Neurological signs were recorded after 7 months but the motor nerve conduction velocities remained normal. Neuropathological examination revealed mild changes in the peripheral nerves but no changes in the central nervous system. 3. The amounts of total lipids and phospholipids were normal, but in all examined tissues the proportions of pentadecanoate (C15 fatty acid) and heptadecanoate (C17 fatty acid) were considerably increased in vitamin B12 deficiency. 4. 3H2O was incorporated to the same extent into the fatty acids of nervous tissue from vitamin B12-deficient and control rats after 48 h. Less 3H was found in the liver fatty acids of the vitamin B12-deficient rats. 5. Neurological dysfunction can be demonstrated in the vitamin B12-deficient rat; the relation of the biochemical and neuropathological changes to the neurological signs needs further study.