METHODS FOR STUDY OF FAT ABSORPTION 133 



modified Babcock technic. 627 Using this procedure, Irwin et al* n were able 

 to obtain concordant results which were much more satisfactory than were 

 those yielded by the chylomicron method. However, the results found by 

 either of these indirect procedures did not parallel the data obtained from 

 the direct absorption tests. Herrmann and co-workers 627 published a de- 

 tailed report on the hemolipokrit method. 



d. Studies on the Portal Blood. Limited information on fat absorption 

 can be obtained by the examination of the portal blood, especially when 

 the composition is compared simultaneously with that from the systemic 

 circulation. By such studies it has been shown that some of the fat may 

 pass into the portal blood, in place of being transported by the lymphatics. 

 However, the concentration of the substance under study in the blood is 

 influenced by so many factors that such a procedure cannot be used as a 

 criterion of the rate of absorption. The technic of angiostomy introduced 

 by London, 628 by which blood can be repeatedly obtained from different 

 vessels without anesthetization, should give results which are more normal; 

 they also offer the opportunity for following changes over a long period of 

 time. 



e. Roentgenologic Method for the Study of Fat Absorption. Groen 629 

 devised a new procedure for following the course of fat absorption which 

 involves the determination of the rate of disappearance of the contrast 

 shadow from x-ray films taken at regular intervals after the oral adminis- 

 tration of "lipiodol." This product is an iodized fat made by treating 

 poppyseed oil with iodine. The extent of excretion of iodine in the urine 

 and stools confirms the x-ray evidence, although the latter data cannot be 

 employed to determine the rate but only the completeness of absorption. 

 This procedure is obviously of value only for determining abnormalities 

 in absorption, and is of no use in assessing the behavior of natural non- 

 iodized oils, since these yield no shadows under the x-ray. 



f. The Use of Radioactive Iodinated Fat. Stanley and Thannhauser 630 

 employed unsaturated fats iodinated with I 131 to study the rate of absorp- 

 tion and of utilization of fats. The proportion of the administered radio- 

 active iodine present in the thyroid gland and excreted in the urine, as well 

 as that in the water-soluble portion of the serum, was shown to give an 

 index to the extent of utilization of the fat. Whereas, in normal subjects, 

 a degradation of 50 to 73% of the orally administered iodinated fat was 



627 L. G. Herrmann, A. Ames, and R. J. Tapke, J. Lab. Clin. Med., 19, 411-421 (1934). 



628 E. S. London, Angiostomie und Organestoffwechsel, All-Union Inst. Exptl. Med., 

 Moscow, 1935. 



629 J. Groen, Am. J. Med., J,, 814-826 (1948). 



630 M. M. Stanley and S. J. Thannhauser, J. Lab. Clin. Med., 34, 1634-1639 (1949). 



