Nandrolone Deconateʼs Effect on Lactate Dehydrogenase Expression in Aged Fast-Type Skeletal Muscle

Abstract

1399 Aging is associated with a decreased plantaris muscle mass and glycolytic and oxidative enzyme activity. Lactate Dehydrogenase (LDH) is an important regulatory enzyme involved in anaerobic glycolysis, and catalyzes the interconversion of lactate to pyruvate. The mechanisms inducing differential LDH expression with advanced age are not well understood. PURPOSE: This study's purpose was to examine aging and anabolic steroid administrations effect on LDH activity and expression in fast-type skeletal muscle. METHODS: Eight 25-month old male Fischer 344XF1 Brown Norway rats were used in this study. Four rats were administered nandrolone deconate (ND), an anabolic steroid with a long biological half-life, every seven days and sacrificed at the end of 4 weeks. RESULTS: LDH-A and LDH-B activity was 71% (p< .001) and 69% (p< .001) lower in aged plantaris muscle compared to young plantaris muscle. LDH-A and LDH-B activity increased 31% (p< .01) and 33% (p< .01) respectively following ND administration when compared to age-matched controls not receiving steroid. LDH protein expression shifted towards the faster LDH isoforms following ND administration in aged plantaris muscle when compared to age-matched controls not receiving ND. CONCLUSIONS: In summary, age induced differential expression of LDH A&B in the rat plantaris muscle, which is partially reversed by ND administration. Supported by a grant from NSF/EPSCOR and NIH/BRIN