1. Kinins have been considered to be involved in the escape from the sodium retaining effects of mineralocorticoids. In a metabolic study in rats, the importance of the kallikrein-kinin system for sodium and potassium excretion was evaluated by aprotinin-induced kallikrein inhibition under basal conditions and during DOCA administration.
2. Kallikrein inhibition was accompanied by a transient sodium retention. The escape from the sodium retaining effect of DOCA was not affected. However, the DOCA-induced potassium loss was enhanced.
3. Kallikrein inhibition decreased urinary prostaglandin (PG) E2 and prevented the DOCA-induced rise in PGE2. Plasma renin activity was stimulated after 10 days of aprotinin administration.
4. The kallikrein-kinin system is not an important mediator of the escape phenomenon but it may play a role in the regulation of sodium and potassium excretion.