DIFFERENCES IN SENSITIVITY TO CA ION LACK BETWEEN MYOBLASTS AND LARGE MYOTUBES FROM CHICKEN BREAST MUSCLE

Abstract

Large myotubes degenerated in Ca-deficient medium containing Mg2+. Numerous vacuoles appeared in the cytoplasm and grew larger. The cells were disrupted and eventually detached from the culture dish. The time course of the destruction process differed from cell to cell. The reduction rate of creatine kinase in the culture dish was constant irrespective of the time after the removal of Ca2+. Most of the myoblasts survived in Ca-deficient medium, after almost all the large myotubes had disappeared. These myoblasts fused to form new myotubes when Ca2+ was supplied. Myotubes formed from myoblasts which had been cultured with Ca-deficient medium for 2 wk also degenerated on Ca removal. Strontium ion added to a Ca-deficient medium did not completely prevent myotube destruction, but decreased their reduction rate.