title: Identification by combined gas chromatography-mass spectrometry of constituent long-chain fatty acids and alcohols from the meibomian glands of the rat and a comparison with human meibomian lipids.
abstract: Constituent long-chain fatty acids and alcohols from the meibomian secretions of the rat were examined as trimethylsilyl (TMS) and methyl ester-TMS derivatives by capillary gas chromatography and by combined gas chromatography-mass spectrometry. The positions of double bonds and methyl branch points were determined by the mass spectra of picolinyl esters and nicotinates for long-chain fatty acids and alcohols, respectively. Fatty acids had chain lengths from C12 to C34 and were of the straight-chain iso, anteiso and monounsaturated types. The unsaturated acids had double bonds in the omega-7 and omega-9 positions. The alcohols had corresponding structures. In common with the constituent acids and alcohols of other meibomian secretions, the chain lengths of the constituents showed a biphasic distribution with maxima around C16-C18 and C25-C27. The profile was qualitatively similar to that obtained from human meibomian secretion but with some differences in the relative proportions of certain acids and alcohols.
mesh_terms: D000818:Animals; D005143:Eyelids / Q000032:analysis*; D005227:Fatty Acids / Q000032:analysis*; D005233:Fatty Alcohols / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008297:Male; D008537:Meibomian Glands / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D013261:Sterols / Q000032:analysis
chemical_list: D005227:Fatty Acids; D005233:Fatty Alcohols; D013261:Sterols