Long-chain fatty acids and alcohols from gerbil meibomian lipids

Capillary gas chromatography-mass spectrometry was used to identify constituent fatty acids, alcohols and steroids from gerbil meibomian glands. Over 80 compounds representing about 90% of the total fraction were identified. The major steroid was cholesterol accompanied by a lower concentration of 3 beta-hydroxy-5 alpha-cholestane. Fatty acids with chain lengths from 12 to 27 carbon atoms were present; they had predominantly straight, iso or anteiso chains with major concentrations in the C15-C18 and C25-C27 regions. Unsaturated acids had mainly 16 and 18 carbon atoms. The fatty alcohols were mainly branched-chain with the majority of compounds having chain lengths of 25-27 carbon atoms. Several alcohols, both branched and unsaturated, were found with chains of up to 33 carbon atoms long. The profile was similar to that found earlier in other species, but with lower concentrations of mono-unsaturated compounds than were found in rats and humans. Di-hydroxy compounds, on the other hand, tended to be more abundant although still of low relative concentration.