Articles : Carnitine Palmitoyltransferase 1 Activity In Various Tissues in Rats

Journal of Exercise Nutrition & Biochemistry 2003;7(3):317-322.

Abstract

Fatty acid oxidation rate is dependent on tissues types. It suggests that the tissue have their own special characteristics to be oxidized for yielding ATP. Our hypothesis is that various tissues have their own specific CPT1 activity as different fatty acid oxidation. CPT1 catalyses the rate-determining step in mitochondria fatty acid beta-oxidation. The enzyme is encoded by at least two genes, on of which is expressed preferentially in liver (L-CPT1) and the other in fat and muscle (M-CPT1). In this study, M_CPT1 activity in two different muscle type of skeletal muscles and two differenet adipose tissues were measured at homogenates and mitochondria. At the same time, L-CPT1 acitvity in hepatic and renal tissues were measured at homogenates and mitochondria, L-CPT1 activity (nmole/min/g) in liver homogenate (416±12) was significantly (p<0.001) higher than in kidney (259±12), M-CPT1 activity (nmole/min/g) in skeletal muscle homogenates were significantly (p<0.001) different between red and white skeletal muscles (RG and WG, 135±12 and 48±5, respectively). M-CPT 1 activity in two adipose tissues homogenate, BAT(388±27) was 20 times higher than WAT(19±4). Mitochondrial L-CPT1 activity (nmole/min/mg) was 1.7-fold higher (P<0.01) in liver (2155±304) than kidney (1293±94). Mitochondrial M-CPT1 activity (nmole/min/mg) in RG (4228±1130) was higher (P<0.05) than in WG (3690±345). M-CPT1 activity (nmole/min/mg) in two adipose tissues (Bat and WAT, 4734±350 and 3294±549, respectiverly) was different (P<0.001) between groups. In conclusion, CPT1 activity was varied greatly depending on different tissue types. It suggests that CPT1 activity must regard to study fat metabolism in various tissues.

Key Words: CPT1, liver, muscle, BAT, WAT, mitochondria