182 II. DIGESTION AND ABSORPTION OF FATS 



Table 26 

 Summary of Results of Absorption of Lower Fatty Acids by Fasting Female 



Rats* 



Absorption, mg./lOO sq. cm./hr. 6 

 Fatty acid fed 1 hr. 3 hrs. 



Acids fed as sodium salts in doses of 100 mg./100 sq. cm. 



Acetic 26.6 ± 1.0(10) 



Propionic 21.4 ± 1.2(16) 



Butyric 39.7 ± 1.5(18) 



45.0 ± 2.6(16) c 



Valeric 23.3 ± 1.9(11) 



Caproic 38.0 ± 1.7(11) 



Heptoic 25.8 ± 1.5(20) 



Acids fed free in doses of 200 mg./lOO sq. cm. 



Caprylic 37.3 ±1.5(23) 46.0 ±1.7(10) 



Nonylic 34.4 ±2.3(24) 32.8 ±1.3(23) 



Capric 19.2 ±1.5(22) 22.6 ±2.1(11) 



Undecylic 21.3 ±3.4(15) 21.4 ±0.5(9) 



Laurie 2.7 ±1.2(10) 3.8 ±0.7(10) 



Tridecylic 20.8 ± 3.2(15) d 



a H. J. Deuel, Jr., L. Hallman, and A. Reifman, J". Nutrition, 21, 373-382 (1941). 

 6 Including Standard Error of Mean. Figures in parentheses indicate number of tests 

 included in the average. 



c L. Bavetta and H. J. Deuel, Jr., Am. J. Physiol, 136, 712-715 (1942). 

 d Diarrhea developed in 16 of 18 rats before 3 hours. 



gut when fed to rats as their sodium salts, 686 or as their triglycerides, 824 

 practically no information has been available until recently as regards the 

 pathway by which they are absorbed. Acetate has been shown to be uti- 

 lized by the phlorhizinized dog, 823 although no clue as to its fate was ob- 

 tained other than to prove that it does not give rise to "extra" sugar. 

 However, the demonstration that C 14 -labeled acetic acid appears in the 

 long-chain fatty acids of milk after its administration to lactating goats is 

 presumptive evidence of absorption and transport to the mammary tissue. 825 

 This subject is discussed more completely in Volume III of this treatise. 

 The proof that propionic acid, when fed as the sodium salt, gives rise to 

 liver glycogen 826 " 828 is sufficient to establish the absorption of this short- 



824 H. J. Deuel, Jr., and L. Hallman, /. Nutrition, 20, 227-232 (1940). 

 826 G. Popjak, Fat Synthesis from Small Molecules, in R. T. Williams, Lipid M etabolism, 

 Biochem. Soc. Symposia, No. 9, Cambridge Univ. Press, 37-51, 1952. 



826 H. J. Deuel, Jr., J. S. Butts, L. F. Hallman, and C. H. Cutler, /. Biol. Chem., 112, 

 15-23 (1935-1936). 



827 H. C. Eckstein, /. Biol. Chem., 102, 591-594 (1933). 



828 J. S. Butts, H. Blunden, W. Goodwin, and H. J. Deuel, Jr., /. Biol. Chem., 117, 

 131-133 (1937). 



