Enzyme activities and activity profiles in muscle fibers of dystrophic, immature-normal, and adult-normal BL6 mice.

Enzyme activities of energy metabolism were determined in both homogenates and single fibers of immature-normal (IN), adult-normal (AN), and adult-dystrophic (AD) tibialis anterior (TA) muscle of BL6 mice. Mitochondrial enzyme activities were similar in AN and AD, whereas lower activities were found in IN. Creatine kinase, glycogenolytic, and glycolytic enzyme activities were reduced but glucose 6-phosphate dehydrogenase was elevated in AD and IN as compared to AN. IN and AD both showed an increase in the H-subunit of lactate dehydrogenase. Microphotometric measurements of succinate dehydrogenase (SDH) revealed large fiber differences in AN whereas smaller scattering was observed both in IN and AD. Although similarities exist between enzyme and isozyme patterns of anaerobic metabolism in AD and IN, this does not hold for mitochondrial enzymes.