PHYSIOLOGIC FUNPTIOXS 825 



free diets, whereas the average vahie for the group receiving 12.5% cotton- 

 seed oil was 64.4 mg. %; this compares with the normal value generally 

 obtained on fat-containing diets devoid of cholesterol. In a later study 

 with weanling rats, Deuel and associates-^ observed that the increased 

 level of liver cholesterol and the decireased figure for blood cholesterol 

 developed Avithin one week after the animals were placed on a fat-free diet. 

 The divergence continued, and increased in the course of the subsequent 

 thirteen-week period during which the test was continued. 



The role of linoleate in cholesterol deposition and transport is not entirely 

 clear. Kelsey and Longenecker-'^ proved that 62% of the plasma choles- 

 terol of cattle occurred in combination with linoleate. It is only natural 

 to postulate that, in the absence of EFA, cholesterol is deposited in the 

 liver, because there is insufficient linoleate available to transport it to other 

 tissues for metabolism and excretion. However, it has been shown that, 

 in such conditions, the increased cholesterol is deposited in the liver as an 

 ester. The cholesterol esters in the liver of rats have been proved by 

 Achaya et al.-^'' to consist almost entirely of those of saturated and oleic 

 acids; only approximately 10% of the cholesterol occurs in combination 

 with linoleic acid, irrespective of whether or not the diet contains EFA. 

 It would thus appear that linoleic acid is of prime importance in the control 

 of the distribution and deposition of cholesterol in the rat. WTiether or 

 not the same situation exists in the case of man is a moot question. 



Mead and his co-workers- ^^ have indicated that ingested polyunsaturated 

 fatty acids appear in the blood largely as sterol esters and phospholipids, 

 whereas oleic and stearic acids appear largely as triglycerides, and slowly 

 appear in the phospholipids. 



The results of Cochrane et al.,~^^ of Ivinsell et aI.,--° and of Kinsell alone^-^ 

 do indicate that a profound relationship may exist in man between the 

 intake of EFA and the level of plasma cholesterol. These workers have 

 reported that elevated levels of blood cholesterol in conditions such as 

 diabetes can be gradually decreased to normal when large amounts of 

 A-egetable fats are included in the diet. On the other hand, this pattern 

 was immediately reversed when animal fats, for instance egg yolk, were 



"6 F. E. Kelsey and H. E. Longenecker, /. Biol. Chem., 139, 727-740 (1941). 

 2" K. T. Achaya, R. B. Alfin-Slater, and H. J. Deuel, Jr., Unpublished results, 1954. 

 *^* J. F. Mead, Personal communication to R. Reiser, 1955. 



2'9G. C. Cochrane, G. I). Michaels, and L. W. Kinsell, ./. Clin. Nutrition, 1, 295-298 

 (1953). 



220 L. W. Kinsell, G. I). Michaels, J. W. Partridge, L. A. Boliiig, H. E. Balch, and G. C. 

 Cochrane, ./. Clin. Nutrition, 1, 224-231 (1953). 



221 L. W. Kinsell, J. Am. Dietet. Assoc, 30, 685-688 (1953). 



