Consumption of kininogen in the submandibular salivary gland when activated by chorda stimulation

1. A method is described for determination of kininogen 1 (substrate mainly for plasma kallikrein) and kininogen 2 (substrate for glandular kallikrein) independently in cat plasma.2. In anaesthetized cats the arterial inflow to, and venous outflow from, the submandibular salivary gland were isolated: a roller pump giving constant volume inflow was interposed in the arterial circuit.3. Venous blood was collected at rest, during and after stimulation of the chorda tympani, and its content of kininogens 1 and 2 were estimated. Kininogen 2 was reduced up to 60% by chorda stimulation, whereas the level of kininogen 1 was unchanged.4. On close arterial infusion of bradykinin or histamine in amounts which produce large vascular effects, including increased capillary permeability, the venous blood levels of both kininogens 1 and 2 were unchanged.5. It is concluded that the selective loss of kininogen 2 on chorda stimulation results from the release of kallikrein into the tissue spaces and reflects the extent of kinin formation within the gland.