lipase action toward various simple esters such as phenylacetate, Glyceryl 

 triacetate, ethyl acetate, and others. Lipase activity also has been found 

 in the spleen, heart, kidney, testes and liver of carp (Kernot and Hills 

 1932). Schmidt-Nielsen and Stene (1938) found "lipase activity" in s almon 

 muscle that was absent in boiled muscle but that could be restored upon 

 treatment with sodium sulfate. It generally is held that before oxidation 

 of fats can occur, the fat must be hydrolized to free fatty acids. Thus 

 these lipases probably perform an essential operation preliminary to the 

 oxidation of fats. 



The phospholipids of several aquatic animals have been investigated: 

 the lecithins, cephalins, and phosphatidic acids of the heart of a ror- 

 qual ( Balaenoptera borealis ); the brain cephalins of the sperm whale ( Phys- 

 ter catodon j and of pollock ( Theragra chalcogramma ); the egg lecithins 

 and cephalins of pollock ( Theragra chalcogramma ) 3 and the cephalins, leci- 

 thins and phosphatidic acids of unfertilized and fertilized eggs of crab 

 ( j^aralithodes camtschatica ) (Igarashi et al. 1956, Zama and Igarashi 1956, 

 and Lama, and hatada 19>6 and 1957). 



Recent compositional studies by Lovern's group have included the 

 fractionation of the various classes of lipids extracted from cod flesh 

 (Garcia et al. 1956). Analysis of the various fractions showed the follow- 

 ing lipids and amounts to be present J lecithin 35 percent, waxes and 

 alcohols 13 percent, free cholesterol 8 percent, phosphatidyl ethanol- 

 amine 7 percent, free fatty acids 6 percent, cholesterol esters 5 percent, 

 triglycerides 3 percent, inositol lipids 2 percent, and unidentified 

 lipids 21 percent. Similar results were found for the lipids of haddock 

 tissue (Olley and Lovern 195U). Triglycerides, hydrocarbons, c hoi ester ol 

 esters, free alcohols, and esterif ied alcohols have been separated by means 

 of silica-gel chromatography from extracts of haddock flesh (Lovern 1956 a)» 

 Determination of the fatty acid components of the cholesterol ester, tri- 

 glyceride, and total lecithin fractions showed them to be characteric of 

 each class of lipids. 



The phospholipid fractions from haddock and from cod flesh have been 

 investigated in more detail by Olley (1956) and Lovern (1956 b). Studies 

 of the distribution of lecithin in sardine revealed the brain to be the 

 richest source, followed by heart muscle (Matsumato 1950) . Red muscle in 

 the sardine was found to contain more than twice the amount of lecithin 

 present in white muscle. 



The sterols, cholic acid and cholesterol, have been identified 

 in the bile of the Spanish tunny-fish (Castells 1953). A new sterol, 

 isolated by chromatographic techniques and comprising about $0 percent 

 of the sterols found in the oyster and in the clam, has been identified 

 to be 2li-methylene-chole sterol (Idler and Fagerlund 1955). Cleland (1950) 

 has determined the contents of phospholipid and neutral fat in unferti- 

 lized oyster eggs and has found lipase to be present (1951), 



NEED FOR RESEARCH 



As this review shows, there is little knowledge of intermediary 

 metabolism of aquatic animals. This lack of information is very undesir- 

 able in studies in the scientific disciplines of biochemistry, biology, 



31 



