Effects of vitamin B 12 deficiency on lipid metabolism of the rat liver and nervous system

Abstract

1. Rats bred from vitamin B 12 -depleted dams were fed on a vitamin B 12 -deficient diet for 12–15 months and developed a severe vitamin B 12 deficiency, as judged from methylmalonic acid excretion and tissue vitamin B 12 levels at slaughter. Control rats were supplemented with vitamin B 12 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 (C 15 fatty acid) and heptadecanoate (C 17 fatty acid) were considerably increased in vitamin B 12 deficiency. 4. 3 H 2 O was incorporated to the same extent into the fatty acids of nervous tissue from vitamin B 12 -deficient and control rats after 48 h. Less 3 H was found in the liver fatty acids of the vitamin B 12 -deficient rats. 5. Neurological dysfunction can be demonstrated in the vitamin B 12 -deficient rat; the relation of the biochemical and neuropathological changes to the neurological signs needs further study.