BEHAVIOR OF ATP-ASE ACTIVITY IN RAT OSTEOCLASTS UNDER THE EFFECT OF CALCITONIN, OR FOLLOWING PRETREATMENT WITH MgCl₂ OR OUABAIN

抄録

This article deals with the behavior of ATPase activity in rat osteoclasts under the effect of calcitonin, or following pretreatment with MgCl₂ or ouabain. Pretreatment with MgCl₂ seems to cause a slight rise of ATP ase activity in various organelles in osteoclasts, but it does not increase the activity of the lysosomal enzyme. It seems that the Mg⁺⁺ ion rather has an effect as a inhibitory agent on the lysosomal ATPase. The plasma membrane of the ruffled border does not possess any significant ATPase activity, hence no reactivation of the enzyme seems to occur by pretreatment with MgCl₂. It is further proved by the finding that ouabain does not inhibit the ATPase activity in the area of the ruffled border. Short term treatment of calcitonin prevents exocytosis temporarily, thereby causing a significant rise of the enzyme activity in various organelles except in lysosomes. The enzyme activity seems to be reduced by serial administration of calcitonin. An endogenous phosphatase activity, being reactive with ATP-omitted medium, is always observed.