FACTORS ALTERING CONCENTRATION OF BLOOD LIPIDS 423 



stored to normal within three hours after the fast was broken by the in- 

 gestion of glucose. 



On the other hand, Man and Gildea 406 noted a decrease of blood lipids 

 associated with undernutrition. Blix, 407 using lipid glycerine as an index 

 of triglyceride fat, found that the triglyceride content of the blood of fast- 

 ing individuals was in the range of 30 to 70 milligram per cent, instead of the 

 earlier values of 150-250 milligram per cent. It has been shown that a 

 hyperlipemia of 2 meq. per liter in plasma fatty acids occurs in children 

 after only twenty-four hours of fasting, and that this elevation still persists 

 after forty-eight hours. Peters and Van Slyke 202 attribute this earlier rise 

 of plasma lipids in children, as compared with adults, to the fact that the 

 former are more susceptible to ketosis than are the latter. It is also known 

 that the monkey, which is like man in developing a fasting ketosis, also 

 develops a rapid hyperlipemia during fasting. 398 These data all fit in with 

 the hypothesis that the hyperlipemia of fasting is related to the attendant 

 ketosis. Cholesterol and phospholipids are the main lipids which bring 

 about the increase in total blood lipids. If the above theory is correct, 

 then the rise in blood lipids should appear more promptly and reach a 

 higher level in women than in men. This would be expected, in view of the 

 fact that ketonuria appears sooner after the start of a fast, and is much 

 more severe during the course of this period, in women than in men. 408 



The serum lipoproteins have been found to be increased in man during 

 fasting. Thus, Rubin and Aladjem 408a reported a significant increase in 

 the concentration of low-density serum lipoproteins in five of six subjects 

 studied within a fast period of four or five days. However, the high-density 

 lipoproteins were not increased under these conditions. The level of 

 blood lipoproteins was restored to normal within twenty-four hours after 

 the resumption of the usual diet, although it was not significantly altered 

 three hours after the ingestion of sucrose. In contradistinction to the 

 results on man, Aladjem and Rubin 408b found that all fractions of lipo- 

 protein (S f 0-12, 12-20, 20-100, 100-400) were significantly increased by 

 fasting for three days, in the case of rabbits. After seven days of fasting, 

 the level of S f 0-12 was further increased, in the blood of the animals, that 

 of the S f 12-20 and 20-100 remained constant, while a drop in the level of 

 the S f 100-400 fraction was noted. 



406 E. B. Man and E. F. Gildea, J. Clin. Invest., 15, 203-214 (1936). 



407 G. Blix, Biochem. Z , 305, 145-149 (1940). 



408 H. J. Deuel, Jr., and M. Gulick, J. Biol. Chem., 96, 25-34 (1932). 

 4083 L. Rubin and F. Aladjem, Am. J. Physiol., in press (1954). 

 mh F. Aladjem and L. Rubin, Am. J. Physiol., in press (1954). 



