Age-related calmitine distribution in mitochondria of normal and mdx mouse skeletal muscle.

In our study, mitochondria were isolated from skeletal muscle in 3-, 5-, 6- and 16-week-old mdx and control mice. A deficit was observed in a calcium-specific mitochondrial protein (named "calmitine") in 3-, 5- and 6-week-old mdx mice but only in 3-week-old control mice. In addition, there was a correlation between the amounts of calmitine and calcium uptake in mitochondria: the latter remained low in 3-, 5- and 6-week-old mdx mice and was similar to controls in 16-week-old mdx mice (as was calmitine). A relationship is suggested between the deficit in calmitine (and calcium uptake in mitochondria) and the important signs of fiber degeneration presented by mdx mice between 3 and 6 weeks of age (a return to normal was observed subsequently).