Presence of T-kininogen and kinins in sponge-induced exudates in rats.

1. The content of kinins and T-kininogen (the third kininogen) in exudates induced by the subcutaneous implantation of saline-soaked sponges have been measured by radioimmunoassay in normal Wistar rats and in Brown Norway rats from a strain which is deficient in high and low molecular weight kininogens. 2. In both strains, sponge implantation induced a rise of T-kininogen in plasma with subsequent accumulation in the sponge exudate. This accumulation correlated with the extravasation of plasma proteins during the first 6 h. Bioassays showed that the T-kinin moiety was retained in T-kininogen. 3. In Wistar rats, a large release of immunoreactive kinins up to a mean value of 6.4 ng ml-1 was observed during the first 6 h and on the second day after the implantation. In Brown Norway rats, the kinin level in the exudates did not exceed 0.53 ng ml-1. 4. Of the kinins present during the first 6 h in the exudates withdrawn from Wistar rats, 60% were identified by high performance liquid chromatography as bradykinin. 5. The volume of the exudate induced by the implantation of dry sponges was smaller in Brown Norway rats than in Wistar rats. 6. We conclude that the role of T-kininogen in this kind of exudate was mainly the inhibition of thiol proteinases and not the release of T-kinin. In Wistar rats, bradykinin acts as a pro-inflammatory factor during the first hours and may play a role during the healing process.