FACTORS ALTERING CONCENTRATION OF BLOOD LIPIDS 427 



clearing of the cloudiness in the plasma obtained during an alimentary 

 lipemia was first recognized, in 1943, by Hahn. 433 Meng and Youmans 434 

 found that when young unanesthetized dogs were injected intravenously 

 with 10% fat emulsion in doses of 1 g./kg. body weight, the administration 

 of heparin reduced the total maximum fatty acid level. The total chole- 

 sterol in the plasma decreased in the heparin-m jected group, in contrast to an 

 increase in the control group. No significant differences in the plasma 

 lipid P in the two groups, respectively, were observed. Block and collabo- 

 rators 435 reported that the injection of heparin caused a greater decrease 

 in the cloudiness of the lipemic plasma of men than in that of women. 



Although turbidity could be decreased in vivo when heparin was injected, 

 the substance does not produce this effect when added to the lipemic serum 

 outside of the body. 433,436 ~~ 438 However, when the heparin reaction has 

 been initiated within the body, it continues when the blood is removed 

 from the body. 439,440 This heparinized plasma has been shown to be ac- 

 tive in the in vitro clearing of a synthetic fat emulsion as well. 441 Anderson 

 and Fawcett 439 interpreted these results as indicating that the injection of 

 heparin activates or stimulates the production of a substance which ap- 

 pears in the plasma, and which possesses "antichylomicronemic" proper- 

 ties. The action of clearing plasma is shared by other heparin-like sub- 

 stances, 442 as well as by a cholesterol-free brain fraction. 443 



The experiments of Anfinsen et a/. 444 confirmed the property of heparin 

 in clearing up lipemic plasma. However, these latter workers demon- 

 strated that heparin alone is inactive, as is a tissue extract prepared from 

 heart. However, when the tissue extract and heparin are combined, the 

 turbidity of lipemic plasma can be reduced. The scheme on the follow- 

 ing page has been suggested by these investigators. 



Brown et a/. 445 reported that the rate of clearing is proportional to the con- 

 centration of co-protein, if the clearing factor is kept at a constant level. 



433 P. F. Hahn, Science, 98, 19-20 (1943). 



434 H. C. Meng and J. B. Youmans, Federation Proc, 12, 424 (1953). 



435 W. J. Block, F. D. Mann, and N. W. Barker, Circulation, 4, 464-465 (1951). 



436 C. B. Weld, Can. Med. Assoc. J., 51, 578 (1944). 



437 J. J. Spitzer, Am. J. Physiol, 174, 43-45 (1953). 



438 A. Comfort, Biochem. J., xxiii (1953). 



439 N. G. Anderson and B. Fawcett, Proc. Soc. Exptl. Biol. Med., 74, 768-771 (1950). 



440 J. J. Spitzer, Am. J. Physiol, 171, 492-498 (1952). 



441 C. Hollett, W. Cole, and H. C. Meng, Federation Proc, 12, 70 (1953). 



442 J. M. Waldron and M. H. F. Friedman, Federation Proc, 7, 130 (1948). 



443 R. J. Jones, S. C. Kraft, E. L. Baiter, and S. Huffman, Federation Proc, 12, 227 

 (1953). 



444 C. B. Anfinsen, E. Boyle, and R. K. Brown, Science, 115, 583-586 (1952). 



446 R. K. Brown, E. Boyle, and C. B. Anfinsen, J. Biol. Chem., 204, 423-434 (1953). 



