Chylomicrons 



465 



The table and curves show that there is no constant relation 

 between the number of chylomicrons and the total fatty acids. 

 In experiments 1 and 2 the chylomicrons reach their maximum 

 in about two hours while the total fatty acids do not reach a 

 maximum until eight hours. Usually the height of the curve 

 for total fatty acids occurs in from 4 to 6 hours after a fat meal 

 but in these two dogs there must have been delayed absorption. 



In experiment 3 there is an increase of the chylomicrons after 

 feeding glycerin but no appreciable change in the total fatty 

 acids. This increase in chylomicrons is similar to experiments 

 reported by Gage and Fish 2 who were inclined to the view that 

 a sufficient amount of fatty acids can be furnished by the tis- 

 sues to build up fat from glycerin that has been ingested. Other 

 investigators have shown that if fatty acids alone are adminis- 

 tered the tissues are able to furnish sufficient glycerin to form 

 fat, and, if the chylomicrons are taken as an index of the 

 amount of fat in the blood it would indicate that the reverse is 

 possible. However, the total fatty acids remain constant 

 throughout this experiment and the increase in chylomicrons is 

 difficult to explain except on the basis that possibly some of the 

 soluble fat in the blood is changed to a visible insoluble fat. 



In experiment 4 the total fatty acids are increased out of all 

 proportion to the increase in chylomicrons. As observed by 

 Horiuchi 1 and Bloor 2 the lipemia produced in rabbits by acute 

 hemorrhage shows a marked increase in cholesterol as well as 

 total fatty acids. The hemorrhagic lipemia has been shown 

 by Horiuchi 5 to be produced on a fat free diet and therefore the 

 increased fat may then originate mainly, if not entirely, in the 

 fat stores. If the chylomicrons are fat, then the fact that there 

 is no great increase of these in this type of lipemia correspond- 

 ing to the great increase of fatty acids would indicate that a 

 large part of the fat is present in the blood in a form not visible 

 under the dark field microscope. 



CONCLUSIONS 



These experiments indicate that there is no constant relation 

 between the total fatty acids and the chylomicrons in the blood 

 after feeding of fat and glycerin, and in the lipemia of rabbits 



l Horiuchi, Y., J. Biol. Chem., 1920, xliv, 363. 

 2Bloor, W. R., J. Biol. Chem., 1921, xlix, 201. 



