SECTION V. LIPIDES ET DÉRIVES D'OXYDATION 



LIPID CARBONYLS AND PRODUCTS OF OXYDATION 



OF LIPIDS 



M. WOLMAN 



Department of Pathology Government Hospital Tel-Hashomer, Israël 



Most lipid carbonyls in animal organs belong to the following three 

 classes of compounds — a) the p 1 asm alo gens; b) the carbonyl containing 

 steroids, and c) the products of oxidation of unsaturated lipids, Besides 

 thèse three classes, carbonylic lipids occur as transitional stages of the 

 beta oxidation of lipids, and thèse mi^t contribute to the staining of 

 tissues by the plasmal techniques. 



Studies of the chemical structure of plasmalogens has shown that they 

 are not acetal-phosphatides, but rather that the fatty aldéhyde is bound 

 in the enolic form by an ether linlc to the glycerol moiety. The chemical 

 group which is responsible for the "carbonyl" reactions is the double 

 bond near the ether link. 



The varions histo-chemical "carbonyl" procédures suggested for de- 

 monstrating ketosteroids stain the same structures as the plasmal and 

 the direct-Schiff reactions although they differ in sensitivity. The inten- 

 sity of staining of varions tissues by ail thèse reactions is increased 

 whenever there is active lipid metabolism in them. This has beën found in 

 the liver, in fat tissue, in the breast, in kidneys and in the adrenals and 

 genitals, during lipid mobilization, lipid déposition, or formation of lipid 

 hormones. The increased stainability of the tissues probably indicates 

 a higher degree of unsaturation which may be due to an increased number 

 of double bonds, or to an increased reactivity of the double bonds, or else 

 to bodi. 



Unsaturated lipids may be oxidized in vitro in the process known as 

 rancidity, during the histological préparation of sections, as well as in 

 vivo by a similar process. During oxidation, epoxides, peroxides, carbo- 

 nyls, 1—2 glycols and carboxyls are formed and the products hâve a strong 

 tendency to polymerize. The process may be self perpetuating by displace- 

 ment of the ethylenic links. The oxidative process can be enhanced by 



oxidation catalysts such as heavy metals, and inhibited by anti-oxidants, 

 such as vitamin E. Thèse data explain the conditions in which chromoli- 



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