Detection of the degradation products of bradykinin by enzyme immunoassays as markers for the release of kinin in vivo.
We developed an enzyme immunoassay (EIA) specific for Arg1-Pro2-Pro3-Gly4-Phe5 ([1-5]-BK) for determination of the levels of this peptide in biological fluids. Previously developed EIAs for bradykinin (BK) and for des-Phe8-Arg9-BK ([1-7]BK) were also used. Incubation of rat plasma with glass powder resulted in the transient appearance of BK. A degradation product, [1-7]BK, could be detected in the incubation mixture for a longer period of time. When compared with BK and [1-7]BK, a larger amount of [1-5]BK was detectable even longer. In carrageenan-induced pleurisy in rats, which was associated with a peak rate of plasma exudation 5 hr after administration of carrageenan, BK was undetectable (< 160 pg/rat) in the pleural exudates. By contrast, [1-7]BK was detectable over the entire course of the inflammatory response. A larger amount of [1-5]BK was detectable. The peak level of [1-5]BK was 6050 +/- 1050 pg/rat, 5 hr after administration of carrageenan. Inhibition of the generation of BK by intrapleural administration of soy bean trypsin inhibitor (0.3 mg/rat) 30 min before collection of pleural fluid resulted in significant reductions in the levels of both [1-7]BK (by 51-65%) and [1-5]BK (by 63-79%) in the exudates 3, 7 and 19 hr after administration of carrageenan. Intraperitoneal administration of captopril (10 mg/kg) caused a marked reduction (by 98%) in levels of [1-5]BK in exudates 3 hr after administration of carrageenan. The reduction was accompanied by an increase in the level of BK up to 1250% of that in untreated rats. These results indicate that the newly developed EIA for [1-5]BK might be a useful tool for verifying the release of kinin in vivo.
Majima
M
M
Department of Pharmacology, Kitasato University School of Medicine, Kanagawa, Japan.
Sunahara
N
N
Harada
Y
Y
Katori
M
M
D000595:Amino Acid Sequence; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D001920:Bradykinin / Q000032:analysis* / Q000097:blood; D002216:Captopril / Q000494:pharmacology; D002351:Carrageenan; D007124:Immunoenzyme Techniques; D008297:Male; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis* / Q000097:blood; D010996:Pleural Effusion / Q000378:metabolism; D010998:Pleurisy / Q000097:blood / Q000139:chemically induced / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012680:Sensitivity and Specificity; D013997:Time Factors; D014358:Trypsin Inhibitor, Bowman-Birk Soybean / Q000494:pharmacology
D015415:Biomarkers; D010446:Peptide Fragments; D014358:Trypsin Inhibitor, Bowman-Birk Soybean; D002351:Carrageenan; D002216:Captopril; D001920:Bradykinin