The Lipid Composition and Na+‐K+‐Dependent Adenosine‐Triphosphatase Activity of the Salt (Nasal) Gland of Eider Duck and Herring Gull

1. The lipid composition of the salt (nasal) gland of eider duck and herring gull, an organ with a high transport capacity for sodium ions, was characterized in detail. 2. The three major lipids of both animals were cholesterol, ethanolamine phosphoglycerides and choline phosphoglycerides. The major fatty acids of ethanolamine phosphoglycerides were stearic and arachidonic acid, and the major fatty acids of choline phosphoglycerides were palmitic, oleic and arachidonic acid. Small amounts of plasmalogens were found. 3. Other phospholipids identified were sphingomyelins, diphosphatidylglycerols, inositol phosphoglycerides and serine phosphoglycerides. 4. The major glycosphingolipids were sulphatides, with similar structure for the two animals. A sulphate group was identified in position 3 of galactose, bound to ceramide mainly containing the C20 homologue of sphingosine and saturated 2-d-hydroxy C22, C23 and C24 fatty acids. No branched-chain or trihydroxy bases were present. 5. An earlier unknown glycolipid, xylopyranosylceramide, was found in small amounts in herring gull but not in eider duck. Glucosyl-and galactosylceramides were present in both animals. 6. The ratio of Na+-K+-dependent ATPase and sulphatides was similar to ratios found for other tissues with increased capacity for the transport of sodium ions. No other lipid resembled sulphatides in this respect.