Identification of main lipid components of mole rat Harderian gland

The Harderian gland of the mole rat has been demonstrated to have appeaseme nt qualities on conspecifics. In this study total lipid content of the Hard erian gland of the mole rat was evaluated and analyzed by means of thin-lay er chromatography (TLC), densitometry, gas chromatography-mass spectrometry (GC-MS), FAB-MS, and NMR. More than 50% of the gland's fresh weight is com posed of lipids, making it the highest Harderian gland lipid content ever f ound in rodents. Male and female lipid components differ considerably. Both have wax esters as the main lipid component, but in females the alcohol co mponents were usually chains of 12 carbons, while in males they were mostly chains of 16 carbons. In addition, while in females the fatty acid residue s were usually saturated, in males there was a double bond in the middle of the chain. As many as 25 different eaters were found in females, and only seven in males. However, in the male an unusual volatile compound identifie d as 1-(3')-hexenyl-benzene was found. This sexual dimorphism may show that the gland function is sex-specific, and gives support to our earlier repor ts that the mole rat Harderian gland may be a source of pheromones.