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Synthesis and secretion of α 2 ‐macroglobulin by human hepatocytes in culture
Author(s) -
PETERSEN C. MUNCK,
CHRISTIANSEN B. S.,
HEICKENDORFF L.,
INGERSLEV J.
Publication year - 1988
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.1988.tb01054.x
Subject(s) - albumin , collagenase , secretion , incubation , hepatocyte , macroglobulin , cell culture , biology , medicine , endocrinology , microbiology and biotechnology , in vitro , biochemistry , enzyme , genetics
Hepatocytes were isolated by application of the two‐step collagenase perfusion technique to pieces of human liver. The cells were incubated in serum‐free medium or 10% FCS‐medium supplemented with insulin, glucagon and dexamethason, and kept in culture for more than 2 weeks. Seventy‐five per cent of the medium was changed regularly and assayed for α 2 ‐macroglobulin (α 2 ‐M), pregnancy zone protein, α 1 ‐antitrypsin and albumin by means of ELISA. Significant amounts of α 2 ‐macroglobulin were present in all cultures. During incubation, α 2 ‐M accumulated in the medium and the quantity of α 2 ‐M released from the cells by far exceeded protein associated with hepatocytes prior to incubation. In 24 h 10 6 hepatocytes secreted 160·5 ± 82·2 ng of α 2 ‐M (mean ± SD, n = 5). Cell‐associated, as well as secreted α 2 ‐M appeared to be on native form, as determined by immunoisolates from lysed cells and culture supernatants. Pregnancy zone protein was only detected in about 50% of the cultures and its rate of secretion was less than 2 ng 24 h –1 per 10 6 cells. In contrast, culture medium contained considerable quantities of α 1 ‐antitrypsin and albumin. In 24 h, 10 6 hepatocytes released > 2 μ g α 1 ‐antitrypsin and > 5 μ g albumin. The present study suggests the hepatocyte to be of major importance for the synthesis of intravascular α 2 ‐M.