A developmental change in the content of parvalbumin in normal and dystrophic mouse (mdx) muscle.

A highly sensitive enzyme immunoassay for mouse parvalbumin was developed in this study. The amount of parvalbumin was determined by a sandwich enzyme immunoassay method using anti-parvalbumin IgG-coated polystyrene balls and an anti-parvalbumin Fab'-horseradish peroxidase conjugate. Parvalbumin could not be detected in normal and dystrophic skeletal muscles of newborn mice. In normal mice, it appeared in the first postnatal week and increased linearly thereafter until the 12th week in fast twitch muscle. Rapid increase in parvalbumin was seen during 3rd and 8th week. On the other hand, parvalbumin detected in the first postnatal week increased gradually, but did not yet reach the adult level at the 16th postnatal week in slow twitch muscle. In mdx mice, fast twitch muscles such as the gastrocnemius and tibialis anterior were found to contain significantly decreased amounts of parvalbumin, compared with those in control mice. In fast twitch muscle parvalbumin in mdx mice could not be detected in the newborn, increased until 4th week and thereafter did not increase as that in normal mice. In slow twitch muscle the postnatal increase in parvalbumin content was not different from that in control mice. These results suggest that the decrease in the content of parvalbumin in dystrophic muscle may contribute to the elevation of the level of sarcoplasmic free Ca2+ and the activated Ca2(+)-dependent proteolysis.