Toxicity of rac-1(3)-myristoyl glycerol to mice.

When a diet containing 30% rac-1(3)-myristoyl glycerol was fed to mice, they developed hypothermia and death occurred within a few days. If 4% safflower oil was added to the diet containing the myristoyl glycerol, hypothermia did not develop and the mortality decreased. There was a pronounced effect of ambient temperature on the toxic effects of rac-1(3)-myristoyl glycerol. Overall, the effects of feeding rac-1(3)-myristoyl glycerol paralleled the previous findings with rac-1(3)-palmitoyl glycerol. Thus there is a general toxicity associated with feeding the monoacylglycerol of any saturated fatty acid that can be reversed by including small amounts of safflower oil in the diet. The only change in plasma lipids that appears to be relevant to the toxicity and its reversal by safflower oil is an increase in cholesteryl linoleate and a corresponding decrease in the cholesteryl ester of the dietary monoacylglycerol. Even though mice ingested large amounts of rac-1(3)-myristoyl glycerol, the percentage of myristic acid in the plasma lipids was not higher than that found when a fat-free diet was fed, and was not affected by the level of myristoyl glycerol in the diet.