Na -K -ATPase 2-gene and skeletal muscle characteristics in response to long-term overfeeding

Ukkola, Olavi, Denis R. Joanisse, Angelo Tremblay, and Claude Bouchard. Na -K -ATPase 2-gene and skeletal muscle characteristics in response to long-term overfeeding. J Appl Physiol 94: 1870–1874, 2003. First published December 20, 2002; 10.1152/japplphysiol.00942.2002.—The role of Na -K -ATPase 2-gene BglII polymorphism in the changes of skeletal muscle metabolic properties after a 100day overfeeding protocol conducted with 12 pairs of monozygotic twins is reported. The activities of oxoglutarate dehydrogenase (OGDH) and phosphofructokinase (PFK) were determined from muscle biopsies. A larger increase in the total fat mass (127 vs. 61%) (P 0.05) and low-density lipoprotein cholesterol (20 vs. 0.7%) (P 0.05) in 8.0/8.0-kb [3.3-kb negative ( ); n 7 pairs] than in 8.0/3.3 3.3/3.3-kb [3.3-kb positive ( ); n 5 pairs] subjects was observed. OGDH activity decreased in 3.3-kb ( 15%), whereas PFK ( 26%) as well as the PFK-to-OGDH ratio (90%) increased. In contrast, among 3.3-kb , OGDH increased ( 54%) together with a decrease in PFK ( 1%) and PFK-to-OGDH ratio ( 5%). These changes were significantly different between genotypes (P from 0.05 to 0.01). In conclusion, fat mass, lowdensity lipoprotein cholesterol, and skeletal muscle glycolytic-to-oxidative enzyme ratio increased more in the 2-gene 3.3-kb subjects with overfeeding, suggesting more unfavorable metabolic changes compared with the 3.3-kb subjects.