Identification of an unusual naturally occurring apolar fatty acid amide in mammalian brain and a method for its quantitative determination.

Fatty acid amides (FAAs), such as the N-acylamides, N-acylethanolamides, N-acyldopamines and N-acylamino acids, are now emerging as an important new class of lipid-signalling molecules. This paper provides evidence, based on high-performance liquid chromatography/electrospray ionisation mass spectrometry (HPLC/ESI-MS/MS), gas chromatography/mass spectrometry (GC/MS) and 1H-NMR, of the occurrence in mouse and bovine brain extracts of a compound characterised by a mass spectrum attributable to a FAA not previously described, namely, the isopropyl-amide of stearic acid (SIPA). A highly sensitive GC/MS method was developed for quantification of naturally occurring SIPA and, also, for purposes of comparison, that of palmitoylethanolamide (PEA), a structurally related compound commonly determined in animal tissues.

Stearoylethanolamide exerts anorexic effects in mice via down-regulation of liver stearoyl-coenzyme A desaturase-1 mRNA expression.

Given the recent demonstration that oleoylethanolamide (OEA), a cannabinoid receptor-inactive N-acylethanolamine, decreases food intake by activating the nuclear receptor PPARalpha (peroxisome proliferator-activated receptor alpha) in the periphery, we here evaluated the effects of both saturated and unsaturated C18 N-acylethanolamides (C18:0; C18:1; C18:2) in mice feeding behavior after overnight starvation. Our results show stearoylethanolamide (SEA, C18:0) exerts, unlike other unsaturated C18 homologs, a marked dose-dependent anorexic effect evident already at 2 h after its intraperitoneal administration. In addition, oral administration of SEA (25 mg/kg) was also effective in reducing food consumption, an effect ascribed to the molecule itself and not to its catabolites.