Effect of Training on Esterified Fatty Acids and Carnitine in Muscle and on Lipolysis in Adipose Tissue in Vitro

The concentration of triglycerides, phospholipids and carnitine was determined in red and white parts of the gastrocnemius muscle from rats with and without a period of training by running. Also the rate of lipolysis in adipose tissue was determined with and without stimulation in vitro . The concentration of triglycerides was reduced in the red and white muscle tissue but positively correlated to each other in white muscle tissue. This suggests that the white muscle tissue. Correlation analysis revealed no direct relationship between the spontaneous or stimulated rate of lipolysis in vitro and the triglyceride concentration in either type of muscle tissue. This suggests that the level of muscle triglycerides was influenced or deter‐mined by other factors than the rate of mobilization of fatty acids from the adipose tissue per se. The concentrations of carnitine and triglycerides were negatively correlated in red muscle tissue but positively correlated to each other in white muscle tissue. This suggests that the metabolic role of carnitine with regard to triglyceride metabolism differed between the two muscle types. The possibility was discussed that the capacity of the intracellular carnitine transport system for fatty acids into mitochondria of red muscle tissue increased in the course of physical training as part of an adaptation towards enhanced oxidative metabolism.