Year: 1974
Type: article
Abstract: Serum-deficient </=0.00003% vol/vol) conditioned medium (CM) obtained from primary cultures of fetal rat hepatocytes initiates DNA synthesis and mitosis in homologous quiescent cultures. CM similarly prepared from 3T3 fibroblast cultures is inactive. At least two conditioning factors are involved in initiating DNA synthesis. The first of these, arginine, is obligatory, synthesized by the cells, and released into the culture medium. The second, a lipid or lipid-containing material, is stable to pH extremes (pH 2, pH 10) and chromatographs with an apparent R(1) approximately 0.5 on silica gel thin-layer plates using hexane-ether (4: 1) as the solvent system. It is suggested that these cultured hepatocytes enter or leave the G(0) or early G(1) phase of the cell cycle as determined in part by their capacity to use available conditioning factor and nutrient components of the medium, in particular, arginine. Serum factors including serum fraction I (4), insulin, and possibly, lipid-like conditioning material appear to initiate DNA synthesis by controlling cellular processes involved with the enhanced utilization and synthesis of growth-limiting nutrients.
Source: The Journal of Cell Biology
DOI: 10.1083/jcb.62.3.780
Authors: K. Koch, H. L. Leffert
Institution: Salk Institute for Biological Studies
Language: English
Subfield: Hepatology
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
Awards: G1379972538, G6629958114
OpenAlex ID: W2047855859