In:
European Journal of Biochemistry, Wiley, Vol. 168, No. 3 ( 1987-11), p. 641-646
Abstract:
Ito cells were isolated from rat liver and kept in culture for up to 13 days. The capability of the Ito cells to synthesize α 2 ‐macroglobulin was analyzed at different times after isolation and by pulse‐chase experiments. Newly synthesized α 2 ‐macroglobulin was determined by immunoprecipitation followed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis and fluorography. α 2 ‐Macroglobulin synthesis was hardly detectable in Ito cells and their media 3 days after plating. However, 5–11 days after the isolation of the cells, increasing amounts of α 2 ‐macroglobulin were synthesized. The results of pulse‐chase experiments performed on day 7 showed that radioactively labeled α 2 ‐macroglobulin decreased in the intracellular compartment and increased in the culture medium. α 2 ‐Macroglobulin was identified by immunoprecipitation and sodium dodecyl sulfate/polyacrylamide gel electrophoresis under reducing and non‐reducing conditions. Furthermore, when unlabeled α 2 ‐macroglobulin was added during the immunoprecipitation a competition was observed. Incubation of pancreatic elastase with culture medium of rat Ito cells or rat hepatocytes led to the same cleavage products as found with α 2 ‐macroglobulin. α 2 ‐Macroglobulin‐specific mRNA could be demonstrated by Northern blot analysis of total RNA extracted from rat Ito cells. Under the conditions where α 2 ‐macroglobulin was synthesized in Ito cells, no synthesis of α 1 ‐macroglobulin, α 1 ‐inhibitor 3, α 1 ‐proteinase inhibitor, α 1 ‐acid glycoprotein, α 1 ‐acute‐phase globulin (T‐kininogen) and albumin could be demonstrated. It is concluded that α 2 ‐macroglobulin is a true secretory protein of rat Ito cells in culture. This could be of importance for collagen metabolism in liver diseases.
Type of Medium:
Online Resource
ISSN:
0014-2956
,
1432-1033
DOI:
10.1111/ejb.1987.168.issue-3
DOI:
10.1111/j.1432-1033.1987.tb13464.x
Language:
English
Publisher:
Wiley
Publication Date:
1987
detail.hit.zdb_id:
1398347-7
detail.hit.zdb_id:
2172518-4
SSG:
12
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