Arginase isoenzymes in human cirrhotic liver.
Cirrhosis leads to an inability of the liver to perform its biochemical functions. It can also lead to hepatocellular carcinoma in which, as we showed lately, arginase isoenzyme pattern changes. The present work presents our results on arginase isoenzymes and their possible role in liver cirrhosis. The study was performed on tissues obtained during liver transplantation from 60 patients with liver cirrhosis, and on samples of histologically normal liver (control) from 40 patients with benign or colorectal cancer liver metastases removed during surgery, 6-7 cm from the tumor border. Arginase isoenzymes AI (so-called liver-type arginase) and AII (called extrahepatic arginase) were identified by Western blotting and isolated by ion-exchange chromatography. Their expression on mRNA level was studied by RT-PCR. A significant decrease in arginase activity, dependent of the liver clinical stage, was observed in cirrhotic tissue. Arginase AI activity and its mRNA level were significantly decreased in cirrhotic liver, whereas the activity and expression of arginase AII were concurrently raised, as compared to normal liver. Since arginase AI is a key enzyme of the urea cycle, whereas arginase AII most probably takes part in the biosynthesis of ornithine and polyamines, the defective ammonia inactivation and increased collagen biosynthesis observed in cirrhotic liver may be related to the changes in arginase AI and AII levels, respectively.
Chrzanowska
Alicja
A
Chair and Department of Biochemistry, Medical University of Warsaw, St. Banacha 1, Warsaw, Poland.
Gajewska
Beata
B
Barańczyk-Kuźma
Anna
A
D000328:Adult; D000368:Aged; D001119:Arginase / Q000235:genetics / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics / Q000502:physiology; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D008103:Liver Cirrhosis / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055815:Young Adult
D007527:Isoenzymes; C477631:ARG2 protein, human; D001119:Arginase