Skeletal muscle lipids

Abstract

• 1.

  1. In order to effectivey explore the physiologic role of lipids in skeletal muscle, a method of analysis is needed to permit the separation and subsequent detailed examinatin of the lipid components. Such a method is described for the quantitative determination of the major and minor classes of lipids present in monkey skeletal muscle. Since the various lipid classes are quantitatively isolated, radioactivity in the lipid components is also easily determined.

• 2.

  2. About one-third of the lipid is neutral lipid and two-thirds phospholipid. The neutral lipid is primarily triglyceride and cholesterol. More than 50% of the phospholipid is lecithin and about 25% is phosphatidylethanolamine. Appreciable quantities of phosphatidylinositol and “polyglycerophosphatide” are also present. The plasmalogen/lipid-phosphorus molar ratio is considerably greater than that reported for muscles of other species.

• 3.

  3. The method was applied to an analysis of monkey gastrocnemius and soleus muscles. The lipid composition of a bilateral pair of muscles is found to be sufficiently similar to permit physiological investigation in which one of the bilateral pair serves as a control as the other undergoes contraction. While the functionally different soleus and gastrocnemius muscles are found to have similar lipid compositions, certain definite differences in the nature of their lipids are uncovered.