Erucic acid metabolism in rat liver. A combined biochemical and radioautographical study

Metabolism of erucic acid was studied in rat liver in comparison with oleic acid in relation with diet lipids. Rats were fed for 3 or 60 days a balanced diet containing 30% of the calories of either rapeseed oil rich in erucic acid or sunflower seed oil rich in linoleic acid. They were intravenously injected with tritiated erucic or oleic acid. After 1 or 15 min, the radioactivity recovered in liver lipids was 9 to 26% whatever the diet or the acid injected. One minute after injection of erucic acid a high part of radioactivity was recovered in the free fatty acid fraction and as untransformed erucic acid. After 15 min the major part of radioactivity was recovered in the triacylglycerol fraction which contained a high proportion of labelled oleic acid formed by shortening of erucic acid. The autoradiography did not show any marked difference between the labelling of peroxisomes and mitochondria when tritiated erucic or oleic acid was injected. These data do not bring about arguments for a peroxisomal nor for a mitochondrial location of erucic acid shortening in liver.