LIPIDS PRESENT IN MUSCLES 733 



Table 3 



Average Cholesterol and Phospholipid Content of Skeletal, Cardiac, 



and Smooth Muscles of General Classes of Animals 



Cold-blooded 

 Category Mammals Birds animals 



Skeletal muscle (thigh) 



Phospholipid, % 4.59 4.34 4.14 



Cholesterol, % 0.27 0.31 0.23 



P:C ratio 17 14 18 



Cardiac muscle (ventricle) 



Phospholipid, % 7.65 7.56 6 00 



Cholesterol, % 0.51 0.54 0.75 



P:C ratio 15 14 8 



Smooth muscle 



Phospholipid, % 3. 52* 2.84' 



Cholesterol, % 0.88 6 0.71' 



P:C ratio 4 4 — 



• Adapted from W. R. Bloor, J. Biol. Chem., 114, 639-648 (1936). 

 5 Tissue includes uterus, stomach, and intestine. 

 c Gizzards of hen, pigeon, owl, and sparrow. 



Kaucher and her associates 198 reported an exceedingly comprehensive 

 study on the lipid composition of the voluntary muscle of a number of 

 mammals, of chickens, of amphibia, and of fishes, as well as of the smooth 

 muscle from the intestine and stomach of cattle. Their data are sum- 

 marized in Table 6 (page 736). 



Although the species examined are for the most part different from those 

 studied by Bloor, 190 the results of Kaucher et al. m offer excellent confirma- 

 tion for the former work. This is especially the case with the phospholipid : 

 cholesterol ratio, which averages 15 for the skeletal muscle of mammals 

 and 4 for the smooth muscle of cattle. The shrimp, whose muscles are 

 largely of the smooth type, has a similarly low P : C ratio. The cholesterol 

 values are exceedingly high in the smooth muscle, which largely accounts for 

 the low P : C ratio. 



Bloor 199 reports that lecithin and cephalin are present in skeletal muscle 

 in about the same amounts, lecithin being somewhat higher ; MacLachlan 200 

 also found a considerably higher lecithin : cephalin ratio for smooth muscle 

 (chiefly uterus) . The results of Kaucher et al. 198 substantiate these results : 

 the lecithin : cephalin ratios in the skeletal muscle of the four mammals 



198 M. Kaucher, H. Galbraith, V. Button, and H. H. Williams, Arch. Biochem., S, 203- 

 215 (1943). 



199 W. R. Bloor, /. Biol. Chem., 72, 327-343 (1927). 



200 P. L. MacLachlan, unpublished results; cited by W. R. Bloor, Biochemistry of the 

 Fatty Aeids, Reinhold, New York, 1943, p. 201. 



