| Abstract |
Liver parenchymal cells from C57BL/6J mouse fetal livers, generally of 16
days gestation, have been grown for over 3 years in continuous culture, in
chemically defined media containing cortisol or dexamethasone at 6x10^-7 M.
In the presence of hormone, sheets of hepatocytes attach and grow. Other
cell types gradually disappear, leaving only hepatocytes. In the absence
of steroid hormone hepatocytes do not survive. After long term growth (1
to 2 years), when the hormone is withdrawn, the cells continue to grow at
a slightly reduced rate. Growth is less vigorous from older fetal or from
postnatal mouse livers. The metabolism of short term cultures has been
investigated, including the utilization of 14C-acetate and 14C-glucose,
the synthesis, turnover, and intracellular location of glycogen, and the
regulation of lipid synthesis. Sterol synthesis is inhibited by
cholesterol. The inhibition is reversible on withdrawal of the cholesterol.
Recovery of sterol synthesis is dependent upon protein synthesis. The
enzyme ornithine transcarbamylase, highly specific for liver, is present
in the parenchymal cell cultures (though the specific activity of the
enzyme decreases following cultivation), and ornithine utilization is
active. Serum proteins are produced. Since liver cells grow well in media
high in K+ and relatively low in Na+ we have studied RNA, DNA, and protein
synthesis in cultures in our usual synthetic medium (MAB87/3 +-
dexamethasone) and in media of various Na+:K+ ratios.
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