ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
It is still a subject of debate whether hepatocytes have the ability to express TGF-β. Therefore, we investigated in freshly isolated and in monolayer cultures of rat hepatocytes the expression of TGF-β isoforms at the RNA and protein level applying RT-PCR, immunocytochemistry, immunoblotting, and functional assays of TGF-β, TGF-β1, -β2, and -β3 transcripts were detected in cultured cells, and the level of mRNA increased up to 48/72 h, but TGF-β1 transcripts were absent in freshly isolated cells. Using APAAP stainings the proteins of all three TGF-β isoforms were observed in hepatocyte cultures from 5-96 h, but in hepatocytes in the liver in situ and in freshly isolated cell suspensions TGF-β staining was negative. SDS-PAGE under reducing conditions followed by Western blotting detected in cell lysates the subunit of mature TGF-β at about 13 kd. Analysis of TGF-β bioactivity with the mink cell (Mv1Lu) proliferation inhibition assay and competitive radioligand assay confirmed in activated (i.e., acidified and subsequently neutralized) hepatocyte-conditioned media the presence of TGF-β, which, however, is almost entirely in the latent form. It is concluded that TGF-β can be expressed in cultured hepatocytes and that the level of expression is quickly upregulated under abnormal, not yet known, microenvironmental conditions. © 1996 Wiley-Liss, Inc.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
