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In vivo metabolism of human tissue‐type plasminogen activator
Author(s) -
Nilsson Torbjörn,
Wallén Per,
Mellbring Göran
Publication year - 1984
Publication title -
scandinavian journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 84
eISSN - 1600-0609
pISSN - 0036-553X
DOI - 10.1111/j.1600-0609.1984.tb02209.x
Subject(s) - trichloroacetic acid , urine , plasminogen activator , metabolism , chemistry , clearance , in vivo , endocrinology , medicine , biochemistry , biology , microbiology and biotechnology , urology
The turnover of human tissue‐type plasminogen activator (t‐PA), purified from cell culture fluids and radiolabeled with 125 I, was studied in 2 healthy males. After injection, the plasma radioactivity initially disappeared with a half‐life of about 3 min, but after 30 min reached a plateau level which persisted for several hours. The radioactive material had then already been converted to forms soluble in 10% trichloroacetic acid (TCA). Surface counting rates indicated a rapid uptake in the liver during the first 10 min after injection, followed by a rapid release from the liver, beginning already at 25 min, which coincided with the appearance of the TCA‐soluble radioactive material. After 18 h, about 80% of the injected dose had already been excreted in the urine. We conclude that, in humans, injected t‐PA is rapidly cleared from the circulation, mainly by the liver, and within 30 min metabolized to low molecular weight forms which ultimately (within 1 d) appear in the urine.