Characterization of cardiac microsomes from spontaneously hypertonic rats

Summary

Capacity of Ca²⁺ sequestration was found to be significantly lowered in microsomal preparations of hearts from spontaneously hypertonic rats. A decrease to 40% of the control level was found for basal and extra ATPase. A similar reduction existed in initial and total Ca²⁺ uptake. These findings are correlated with a lower concentration of the Ca²⁺ transport ATPase in SDS gel electrophoresis, a lower density of the 7–9 nm intramembraneous particles and higher half-lives of phosphoprotein. Altered contractility of hypertrophied myocardium may thus be partially explained by the dysfunction of the Ca²⁺ sequestering system.

This study was supported by the Deutsche Forschungsgemeinschaft, Sonderforschungsbereich 138 “Biologische Grenzflächen und Spezifität”.

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