To investigate the possible changes in pyruvate oxidation during the rapid growth period in an animal model, the oxidation of radioactive labeled pyruvate was measured in mitochondria isolated from the gastrocnemius muscle of Sprague--Dawley rats between 4 and 16 weeks of age. The influence of the fatty acid derivative palmitylcarnitine, as an inhibitor of pyruvate oxidation, was also tested.The gastrocnemius muscle was removed from anesthesized animals at 4, 8 and 16 weeks of age. Isolated mitochondria from the muscle samples were incubated with C1--14C] pyruvate and E1-14C] pyruvate + palmitylcarnitine in a KC1 medium. The decarboxylation of pyruvate was measured by the evolution of radioactive labeled carbon dioxide. Pyruvate oxidation significantly (p .; 0.0001) increased from ages 4 to 16 weeks. The initial low rate of pyruvate oxidation was attributed to the residual metabolic effects of the pre-weaned animal' high-fat diet. The subsequent increase in the capacity of pyruvate oxidation was then explained by the shift in the animaldiet to high-carbohydrate lab chow. These results may also be attributed to the maturation of the hindlimb muscle fibers during this period: the differentiation of predominately red, oxidative fibers to an increase in the percentage of white, glycolytic fibers, common in the adult hindlimb. The fatty acid derivative, palmitylcarnitine, failed to inhibitpyruvate oxidation at the level of decarboxylation. This finding supports the proposal that fatty acids do not inhibit glucose oxidation directly, but instead suppress glycogen breakdown. Thus, the findings indicate an increase in the capacity for- pyruvate oxidation during the rapid growth period without inhibition by the fatty acid derivative, palmitylc_arnitine. / Department of Biology
| Identifer | oai:union.ndltd.org:BSU/oai:cardinalscholar.bsu.edu:handle/183791 |
| Date | January 1989 |
| Creators | Stroup, Laurie B. |
| Contributors | Ball State University. Dept. of Biology., Craig, Bruce W. |
| Source Sets | Ball State University |
| Detected Language | English |
| Format | vi, 58 leaves : ill. ; 28 cm. |
| Source | Virtual Press |
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