Presence of a fast-acting specific inhibitor of plasminogen activator in human parotid saliva.
The plasminogen activator in parotid saliva has recently been characterized as a tissue-type plasminogen activator (t-PA). In this study stimulated parotid saliva from 21 healthy volunteers was analysed for (a) t-PA activity using the fibrin plate assay or a bioimmunoassay coupled to the plasmin-specific chromogenic substrate S-2251, (b) t-PA antigen using an enzyme-linked immunospecific assay and (c) activity of the specific fast-acting plasminogen activator inhibitor (t-PA inhibitor) assayed by its inhibitory effect on one-chain t-PA added to the samples. In parotid saliva the median t-PA activity was 0.2 IU ml-1 (normal range 0.05-0.35 IU ml-1), but activity of free t-PA could not be demonstrated by bioimmunoassay in any sample. The mean antigen concentration of t-PA was 2.2 IU ml-1 in the 10 samples with levels above the detection limit (0.5 IU ml-1). High activity of t-PA inhibitor was demonstrated in all parotid salivas, and the mean inhibitory effect on t-PA was 13.2 IU t-PA quenched per millilitre. This study thus demonstrates a fibrinolytic system in parotid saliva characterized by high t-PA inhibitor activity and relatively low concentration of inactive, probably complex-bound, t-PA which is activated in the presence of fibrin.
Kjaeldgaard
A
A
Department of Obstetrics and Gynaecology, Huddinge University Hospital, Sweden.
Kjaeldgaard
M
M
Gaffney
P
P
D000328:Adult; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005342:Fibrinolysis; D006801:Humans; D007118:Immunoassay; D008297:Male; D008875:Middle Aged; D010306:Parotid Gland / Q000032:analysis*; D012463:Saliva / Q000032:analysis*; D010959:Tissue Plasminogen Activator / Q000032:analysis*
D010959:Tissue Plasminogen Activator