Determination of bradykinin-(1-5) in inflammatory exudate by a new ELISA as a reliable indicator of bradykinin generation.

We have developed an ELISA for BK-(1-5) (Arg1-Pro2-Pro3-Gly4-Phe5). In rat carrageenin-induced pleurisy, in which a plasma exudation peak was observed 5 h after carrageenin, BK levels in the exudates were negligible (< 60 pg/rat). BK-(1-7) (des-Phe8-Arg9-BK) was detectable (900-400 pg/rat) over the entire course of the inflammation. However, a larger amount of BK-(1-5) was detectable in association with the increase in plasma exudation, showing a peak (8800 +/- 1200 pg/rat) 3 h after carrageenin. Bromelain (10 mg/kg, i.v.) and soy bean trypsin inhibitor (0.3 mg/rat, intra-pleural) significantly reduced BK-(1-5) levels (by 60-93%, 3, 7 and 19 h after carrageenin) and plasma exudation rates (by 61-74%, 3 and 7 h after carrageenin). Dexamethasone (0.3 mg/kg, i.p.) reduced BK-(1-5) levels (by 78%) and decreased plasma exudation (by 70%) 3 h after carrageenin. In nasal allergy patients, antigen challenge of nasal mucosa elevated BK-(1-5) levels and active kallikrein levels in nasal washes. These results verify that BK-(1-5) determined by ELISA is a good indicator for release of kinins in vivo.