Toxicity of rac-1(3)-palmitoyl glycerol in weanling mice.

Reinvestigation of the previously reported toxicity of saturated fat on weanling mice has shown rac-1(3)-palmitoyl glycerol to be a more potent toxic agent than free palmitic acid when fed as the sole source of dietary fat. As shown before, protection against this toxicity can be afforded by the addition of 2 to 4% safflower oil. We have now shown that if the rac-1(3)-palmitoyl glycerol is acetylated the toxicity is much less. The protective effect of diacetyl rac-1(3)-palmitoyl glycerol cannot be totally ascribed either to the presence of acetate itself or to the blocking of the free hydroxyls of palmitoyl glycerol by acylation. In vivo absorption studies coupled with in vitro experiments with pancreatic lipase suggest that the major protective effects result from increased lipolysis of the acylated palmitoyl glycerol, causing conversion to the less toxic free palmitic acid.