Summary:The catalytic activities of 4 glycosidases (hyaluronate-4-glycanohydrolase (EC 3.2.1.35), Ă-Nacetyl-D-glucosaminidase (EC 3.2.1.30), Ă-glucuronidase (EC 3.2.1.31), -L-iduronidase (EC 3.2.1.76)), of the arylsulphatases A and B (EC 3.1.6.1) and of the protease cathepsin D (EC 3.4.23.5) were measured in extracts from hepatocytes and non-parenchymal cells and in serum during the development of thioacetamideinduced rat liver fibrosis (22 weeks). In non-parenchymal liver cells the catalytic activities of Ă-N-acetyl-Dglucosaminidase, Ă-glucuronidase, -L-iduronidase and cathepsin D were increased significantly during chronic liver damage, but that of hyaluronate-4-glycanohydrolase was reduced by 40 to 65% during the period of applicĂ€tion of thioacetamide. The catalytic activities of the arylsulphatases were lowered by 65% compared to control values in the 12th week but with advancing liver damage the catalytic activities returned to nearly normal values. Parenchymal cells of rats, which had been liver-damaged for 6 months, contained strongly elevated activities of Ă-glucuronidase, Ă-N-acetyl-D-glucosaminidase, arylsulphatases A and B, and cathepsin D but only slightly increased activities of hyaluronate-4-glycanohydrolase and -L-iduronidase, respectively. In the serum of liver-damaged rats the activity of -L-iduronidase was strongly elevated, while that of Nacetyl-Ă-D-glucosaminidase was only slightly increased. The activities of Ă-glucuronidase and of arylsulphatases A and B were decreased during the whole period of treatment. The catalytic functions of hyaluronate-4-glycanohydrolase and of cathepsin D, respectively, were decreased initially, but both enzyme activities were elevated during the more advanced stages of long term thioacetamide treatment.
AktivitĂ€tsĂ€nderungen Proteoglykan^abbauender^ lysosomaler Enzyme in Parenchym-und Nicht-Parenchymzellen der Leber sowie im Serum wĂ€hrend der Entwicklung einer experimentellen LeberfibroseZusammenfassung: Die katalytischen AktivitĂ€ten von vier Glykosidasen (Hyaluronat-4-glykanohydrolase (EC 3.2.1.35), Ă-N-Acetyl-D-glucosaminidase (EC 3.2.1.30), Ă-Glucuronidase (EC 3.2.1.31), cc-LIduronidase (EC 3.2,1.76)) sowie zweier Sulfatasen (Arylsulfatase A und B) (EC 3.1.6.1) und einer Protease /(Kathepsin D) (EC 3.4.23.5) wurden in den löslichen Extrakten von Hepatocyten und Nicht-Parenchymzellen der Leber und im Serum im Verlaufe einer Thioacetamid-induzierten Leberfibrose (22 Wochen) bestimmt. In Nicht-Parenchymzellen sind die katalytischen AktivitĂ€ten der Ă-N-Acetyl-ÂŁ>-glucosaminidase, Ă-Glucuronidase, -L-Idufonidase und Kathepsin D bei chronischer LeberschĂ€digung signifikant erhöht, wohingegen die katalytische AktivitĂ€t der Hyaluronat-4-glykanohydrolase im gesamten Untersuchungszeitraum um 40 bis 65% vermindert ist. Die katalytischen AktivitĂ€ten der Arylsulfatasen A und B waren in der 12. Woche der SchĂ€digung um 65% erniedrigt (verglichen mit den Kontrollen), mit fortschreitender LeberschĂ€digung wurden jedoch wieder Normalwerte erreicht. Parenchymzellen von Ratten, die 6...