Abstract
Effects of aldosterone and puromycin, alone or in combination, on kidney carbonic anhydrase and ATPase activities and/or urinary excretion of sodium were investigated using adrenalectomized and normal mice to clarify the significance of above enzymes in induction hypothesis of aldosterone.
1. In adrenalectomized mice, puromycin had no effect on the activities of kidney carbonic anhydrase and Na+-K+-ATPase and on urinary excretion of 22Na.
2. Combined administration of puromycin with aldosterone inhibited both the elevation of kidney carbonic anhydrase activity and decrease of urinary excretion of 22Na induced by aldosterone alone, whereas Na+-K+-ATPase activity had no relation with puromycin.
3. Time-course of effect of puromycin was examined in normal mice. Puromycin (1-125 mg/kg, i.p.) inhibited kidney carbonic anhydrase activity and its maximum effect was observed at 4 hr after injection without any alterations in Na+-K+-ATPase activity.
In conclusion, the elevation of kidney carbonic anhydrase activity by aldosterone in adrenalectomized mice may be due to the increased synthesis of this enzyme, which may have a correlation with aldosterone-induced decrease of urinary excretion of sodium.
