Plasminogen activator in normal subjects after exercise and venous occlusion: t-PA circulates as complexes with C1-inhibitor and PAI-1.
Exercise to exhaustion was associated with the appearance in plasma of plasminogen activator (PA) in several mol wt forms, as identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with zymography. A number of active bands, all immunologically identified as tissue-type PA (t-PA), were observed. The major form had an apparent mol wt of approximately 60,000 and is due to free t-PA. The other strong bands had apparent mol wts of approximately 110,000 and 180,000. The 110,000 band, also present in pre-exercise samples, represents t-PA complexed with its major inhibitor (PAI-1), and the 180,000 band is due to t-PA complexed with C1 inhibitor. The released forms of t-PA were cleared rapidly after cessation of exercise at exhaustion. Urokinase-type PA (u-PA) activity was also identified in pre- and postexercise samples at an apparent mol wt of approximately 50,000. This is consistent with its being free u-PA; no complexed forms of u-PA were observed. Qualitatively similar changes in plasma PA were observed after venous occlusion. Small quantities of plasmin were generated after strenuous exercise, as observed by detection of plasmin-alpha 2-antiplasmin complex by two-dimensional immunoelectrophoresis in three of five subjects. This complex was cleared rapidly after cessation of exercise. Plasmin-alpha 2-antiplasmin complex was not detected in any of the subjects after venous occlusion.
D005341:Fibrinolysin / Q000378:metabolism; D006023:Glycoproteins / Q000502:physiology; D006801:Humans; D005082:Physical Exertion; D010960:Plasminogen Activators / Q000032:analysis*; D015849:Plasminogen Inactivators; D013924:Thrombophlebitis / Q000378:metabolism*; D010959:Tissue Plasminogen Activator / Q000502:physiology; D014568:Urokinase-Type Plasminogen Activator / Q000502:physiology
D006023:Glycoproteins; D015849:Plasminogen Inactivators; D010960:Plasminogen Activators; D010959:Tissue Plasminogen Activator; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator