Clearance of the alpha(2)macroglobulin-trypsin complex and uptake of trypsin by perfused liver

Clearance of the alpha(2)macroglobulin-trypsin complex and uptake of trypsin by perfused liver

Author Nagaoka, Márcia Regina Autor UNIFESP Google Scholar
Kouyoumdjian, Maria Autor UNIFESP Google Scholar
Borges, Durval Rosa Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Abstract The uptake and degradation of the alpha(2)macroglobuin-trypsin (alpha(2)m-trypsin) complex have been studied using isolated liver cells but not in the liver as a whole. We report the clearance of the complex by the isolated and exsanguinated liver of Wistar male rats, weighing 150-280 g, and compare it with that of the free enzyme. The hepatic clearance of the alpha(2)m-trypsin complex follows a pattern with a distribution phase followed by an elimination phase, which contrasts with that of trypsin where only the distribution phase is observed. The extraction of trypsin from the perfusate is Ca2+-independent (156 +/- 14 pmol/g liver in the presence of 2.5 mM Ca2+, N = 9, versus 140 +/- 8 pmol/g liver in its absence, N = 7) and is not affected by 100 mM NH4Cl (152 +/- 7 pmol/g liver, N = 6), 100 U/ml heparin (164 +/- 14 pmol/g liver, N = 5), 30 mu l/ml carbon particle suspension (150 +/- 13 pmol/g liver, N = 7) or an acute-phase situation induced by turpentine (125 +/- 10 pmol/g liver, N = 6) (P>0.05, ANOVA). The hepatic clearance of the alpha(2)m-trypsin complex is Ca2+-dependent (1.8 +/- 0.2 ml/min in the presence of Ca2+, N = 8, versus 0.6 +/- 0.03 ml/min in its absence, N = 4), affected by NH4Cl (<0.1 ml/min, N = 7), heparin (1.1 +/- 0.2 ml/min, N = 6) and the acute-phase (0.6 +/- 0.1 ml/min, N = 6) but not by the carbon particle suspension (1.8 +/- 0.2 ml/min, N = 7). These results show that trypsin is not internalized by hepatocytes (no NH4Cl effect) or Kupffer cells (no carbon particle effect) and that the alpha(2)m-trypsin complex is internalized in a Ca2+-dependent process by hepatocytes, but not by Kupffer cells, and is affected by an acute-phase reaction.
Keywords trypsin
alpha(2)macroglobulin
alpha(2)m-trypsin complex
liver clearance
acute-phase reaction
Language English
Date 1996-06-01
Published in Brazilian Journal Of Medical And Biological Research. Sao Paulo: Assoc Bras Divulg Cientifica, v. 29, n. 6, p. 797-803, 1996.
ISSN 0100-879X (Sherpa/Romeo, impact factor)
Publisher Assoc Bras Divulg Cientifica
Extent 797-803
Access rights Closed access
Type Article
Web of Science ID WOS:A1996UU92200014
URI http://repositorio.unifesp.br/11600/43110

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