1 16 II. DIGESTION AND ABSORPTION OF FATS 



such as that in egg yolk and in milk may undergo some hydrolysis. Re- 

 gurgitation of intestinal contents, likewise, may aid in gastric lipolysis, 

 both by changing the pH of the medium to one nearer the optimum for 

 gastric lipase, and by supplementing the gastric enzyme with the pancreatic 

 lipase. 



Some absorption of foodstuffs has been demonstrated in the stomach 

 of animals following ligation of the pylorus, but such substances would 

 ordinarily leave the stomach quickly if the pylorus were functioning nor- 

 mally, and digestion would not have proceeded far enough, under usual 

 conditions, to allow any absorption. Klemperer and Scheurlen 588 demon- 

 strated that no fat was absorbed during a period of three to six hours in 

 dogs, when a ligature had been placed around the intestine just below the 

 pylorus. Moreover, the stomach mucosa is not adapted to absorption. 



However, several workers have demonstrated, by histological examina- 

 tion, the presence of fat droplets in the gastric epithelium after fatty 

 meals. Weiss 589 believed that this absorption occurred only in young 

 animals, but Greene and Skaer 590 noted similar fat droplets in the gastric 

 mucosa of old dogs, as well as in the mucosa of young animals. The histo- 

 logical picture of the gastric mucosa resembled, to a considerable extent, 

 that of the intestinal mucosa during fat absorption. After the fat had left 

 the stomach, the cycle was reversed, and the fat disappeared from the mu- 

 cosa. Mendel and Baumann 591 found some fat droplets in gastric mucosa, 

 as determined histologically and chemically, but they could detect no 

 concomitant change in the level of blood fat. Inouye, 692 however, was able 

 to demonstrate a slight increase in the fat content of thoracic lymph when 

 fat was present in the stomach, although the rise was a minor one. 



Finally, one must conclude that, normally, the stomach is not the site 

 of absorption of fat, but that the gastric mucosa can take up fat temporarily 

 in a manner similar to that of the intestinal mucosa. However, since the 

 stomach mucosa is not adapted to complete the absorption, the fat drop- 

 lets disappear when the food fat has passed into the intestine. The chief 

 function of the stomach seems to be to free the fat from protein by digestion 

 of the latter, to bring about a small amount of hydrolysis of the fat with the 

 formation of fatty acid, and thus to provide ready material for the forma- 

 tion of enough soap to aid in prompt emulsification when the chyme passes 

 into the small intestine. Apparently, the stomach also regulates the entry 



588 G. Klemperer and E. Scheurlen, Z. klin. Med., 15, 370-378 (1889). 



589 O. Weiss, Arch. ges. Physiol. (Pfluger's), 144, 540-543 (1912). 



590 C. W. Greene and W. F. Skaer, Am. J. Physiol, 32, 358-368 (1913). 

 691 L. B. Mendel and E. J. Baumann, /. Biol. Chem., 22, 165-190 (1915). 

 592 T. Inouye, Am. J. Physiol, 69, 116-124 (1924). 



