CORRELATION OF SUPPRESSED LINOLEIC-ACID METABOLISM WITH THE HYPOCHOLESTEROLEMIC ACTION OF ERITADENINE IN RATS

The dose-dependent effects of dietary eritadenine on the metabolism of linoleic acid and on the plasma cholesterol concentration were invest igated to clarify the mechanism of the hypocholesterolemic action of e ritadenine in rats. Rats were fed control or eritadenine-supplemented (2 to 20 mg/kg) diets for 14 d. Eritadenine supplementation significan tly decreased both the plasma cholesterol concentration and the 20:4n- 6/18:2n-6 ratio of liver microsomal and plasma phosphatidylcholine (PC ) in a dose-dependent manner. Eritadenine was also found to decrease t he activity of Delta 6 desaturase in liver microsomes; there was signi ficant correlation between the Delta 6-desaturase activity and the 20: 4n-6/18:2n-6 ratio in the PC of liver microsomes (r = 0.989, P < 0.001 ) or plasma (r = 0.986, P < 0.001). Certain plasma PC molecular specie s, as represented by 16:0-18:2, were increased by eritadenine in a dos e-dependent manner, and certain plasma PC molecular species, as repres ented by 18:0-20:4, were conversely decreased by eritadenine. There wa s a significant correlation between the plasma total cholesterol conce ntration and the proportion of the sum of plasma PC molecular species which contain 18:1 or 18:2 in the sn-2 position. These results support the idea that the suppression of linoleic acid metabolism by eritaden ine might be associated with the hypocholesterolemic action of eritade nine.