Abstract
1. A long continued hyperplasminemia was produced by the consecutive administration of Mitomycin C to rabbits.
2. An activator activity was observed in kidney parenchyma and kidney pelvis when the activator was extracted from fresh tissue with 2M KCI or 300/, sucrose.
3. The activator activity of kidney parenchyma was completely disappeared after administration of Mitomycin C, while variation of the activity of pelvis was not significant even after the administration. The disappearance of activator activity was not explained by the increasing inhibitory action in kidney parenchyma.
4. The recovery of the activator activity of kidney parenchyma was well demonstrated several days after ceasing the administration of Mitomycin C.
